Can't really add any solutions, as most have been said already. However, I am just curious if the lump is on the top of your wrist? Growing up, I was a writer. (Feeling old, there were no laptops then lol) Constantly writing, hours a day sometimes. My right hand developped something like a cyst on the top that would flare up and feel how you described yours. Really painful, and crippling to the point that I could hardly hold a pen or pencil when it was bad, as well as lifting/holding weighted things (like my school bag strap). Also developped a calous(?) on the inside of my middle finger, I would bite it off lol. After years of not writing so much, the cyst rarely flares up, although the calous is still there. I actually taught myself to write completely different from usual and rotate them.