What can i do if my hand/wrist cramps up like crazy when i play bar chords on my guitarouch and help!?

Overuse, Weakness: Did you start to play more recently? I treat a lot of musician's and this is a common problem. The cramping is most likely due to over use, hand weakness, or possibly a pinched nerve. Make sure your warm up before you play(big muscles), play for 15-20 minutes then take a break. A hand therapist can give you exercises to strengthen your hand.