My shoulders, forearms & wrists hurt

Find a better sitting position. Or take a break. This can be as simple as moving from your breakfast table to the couch or your desk, or it can be as complex as buying a new ergonomic chair and desk set. You will lose track of time while on the PC (or tablet), and extended computing can introduce repeated stress injuries. 

At the very least, get up and move around every couple of hours. Your digital life will still be there when you get back.