What Causes Sharp Pains In My Joints While Trying To Write?

i write a lot and i have noticed lately that while writing my hand will start to tense up and it gets hard to write. Then today I noticed that between my joint (that general area, next to the funny bone) has been having really sharp pains when i write, make sudden movements or type. the thing is i go to school daily and have to write constantly, or else i would rest it. any suggestions?