When I use my right hand to do something like putting a cable line in the cback of my tv I get a sudden tightening and my fingers and sometimes thumb lock or go all shapes that I then cant control and if I dont grab my fingers quickly enough the pain in my forearm hurts bad. I now bend my fingers right back to stretch my tendons because i feel its the tendons tightening. I just wonder is it because i sometimes suffer dehydration .
Any ideas as why this is happening besides old age of course lol ???.