.

its okay, the pain just means you need to practice more

your index, middle and thumb (possibly index, ring and thumb) don't get numb sometimes, do they?

Nope.

okay, just making sure lol

I went to the doctor to test for RSI/carpal tunnel when I was having similar problems. The tests they had me do included:

-Ability to freely rotate wrist/thumb in all dimensions without pain
-Be able to grip a sheet of paper between your thumb & index finger and not be able to pull it out
-Check for numbness

This is by no means a comprehensive list (AND I'M NOT A DOCTOR), but if you're doing good in these areas, you probably are just gaming too much and need to take more frequent breaks.

Play guitar for a decade. Your fingers will never be sore again.
Yay for calluses

Take a break and rest it.

Use your entire arm and not just your wrist/fingers when aiming, spread out the muscle groups used and you'll not strain particular groups as much.

I would just go to the doctors just in case. I have the same problems now, but they were a result from a car accident. Basically, I can't play MGE for more than a round or two, but I am able to play soap for a little longer. The way I see/feel it when it comes to gaming is that the constant tracking seems to be the worst. I just noticed that I have zero suggestions, other than stretching and not to play too often. The best thing that you can do, if you have it, is to make sure to not make it worse.

https://www.youtube.com/watch?v=hUyMNyrOHJQ

I've seen this video linked a good amount of times in the SC2 community.

My wrists got pretty bad at one point, with occasional numbness in my pinky and ring fingers, and occasionally I'd wake up and find that bending my wrist any amount would result in excruciating pain.

I "fixed" it by doing a good amount of those types of wrist stretches, and always making sure I try to sleep with my wrists straight.
Also, when you're playing TF2 or whatever, take mini breaks by lifting both hands off the mouse/kb and giving them a quick stretch. (I usually will spread my fingers as far as I can, then ball up into a fist and rotate my wrist back and forth on its natural axis.)

Edit: Also take a break, as others have suggested.

Thanks for all the advice. I did some experimenting and using my keyboard on my lap helped that wrist quite a lot.

I think I'll go with the most common advice in here though, and take more breaks or just play less frequently in general. Probably won't hurt me to play less video games.

https://www.youtube.com/watch?v=SSbf4mBKq-o

I started using these

http://i.walmartimages.com/i/p/00/70/25/56/00/0070255600601_500X500.jpg

I also made sure to stretch before games and in between.

SC2 is a killer for me :P

As someone that has arthritis and what sometimes feels like carpal tunnel at times too I did see my doctor about this. I was using a computer for well over 8 hours everyday, the pain was constantly there and it hurt.. a lot. Even with pain killers they were still driving me crazy and limiting my movement.

The video that was linked is great, it actually has a couple of the stretches I was going to suggest. The last one is really good. For me when the pain flares up it extends through my entire arm, so I try to make sure that I do stretches for my entire arm and neck as well. I was trying to find the link to the site I used to use, but I couldn't find it. :(

http://www.ehs.utoronto.ca/services/Ergonomics/exercise.htm
Luckily I was able to find a link that had my entire stretching routine I did before using the computer. I didn't do that first one, but all of those are really good for you, especially paired with the stretches from that video. I also pulled back each finger individually for about 8 seconds.

Then the slightly unfortunate part is I have been forced to use the computer less than I used to. It's good because I do other things now to fill the time and get away from the screen, but it is hard to pull back sometimes. Even taking a 15 minute break makes a world of difference for your arms, and your eyes too.

Hope these help, I know they have made a world of a difference for me.

Whereabouts do you feel the pain? Like mostly in the joints?

Great link PrettyPrettyPrincess.

My entire mouse arm is pretty tense while playing, and thus gets sore, but I think this is more normal.
On the other arm, it's my wrist and forearm (mostly the area close to the wrist and the long large muscle along the top), as well as the fingers.

So far stretching and giving your hands a rest every few minutes have been good suggestions. At the end of the day I would suggest even a heat pack on your arms and hands to relax them.
Stretches should be held for 30 seconds aaaalways and done twice a day.

What's your mouse and keyboard setup like? (pictures, preferably)

Make sure you're sitting right, I used to have a slight tightness in my arm a few years ago and it's because my arm wasn't being supported by shit.

http://images.teamsugar.com/files/upl1/1/12981/22_2008/DeskErgonomics.jpg

This bitch be doing it right.

You don't want to use heat at all. If there is a long term stress injury heating it will cause it to swell and worsen the problem. Icing it will do a lot more good, especially if it's a condition like carpal where the inflammation is pinching the nerves.

http://i.imgur.com/ZCzo9qQh.jpg

Would perhaps russian style, with my elbow on the desk be a healthier choice? Relaxing my other hand since it can rest on my lap. Of course the compromise would be having my face a lot closer to my monitor. Not sure how much of the eyesight stuff is myths, but I can't imagine that being healthy.

Do you have skinny forearms? Strengthening your forearms or training them for more endurance will probably be an easier fix for a young kid like you. There's some really easy forearm exercises you can do with a 5-10lb dumb bell and it will definitely make a big difference.

Should they look like this?

https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-ash2/327576_10151006797915585_1835534705_o.jpg

.

The thing that I never understood about the Russian style is would being that close to your monitor be really bad for your eyes?