It IS something you're going to have to figure out for yourself, possibly with the help of a qualified medical practitioner.

It DOES sound like some form of tendonitis, and rest can help. Complete immobilization may hurt more than help. Anti-inflammatories may help, and the over-the-counter ones can be quite effective.

Inflammation is part of the healing process, but if you don't give whatever it is a chance to heal, the inflammation just gets worse. Cortisone reduces/stops the inflammation, so that may be what Gurney's talking about. (It may go farther than that, but I don't believe so.) I had a cortisone injections once, for my shoulder. It worked, and I've had very infrequent and minor pain since - mostly when I do things I know I shouldn't.

GUEST,smokeyjoe, that "swelling up like sausages" thing would scare the crap out of me. If it was some form of arthritis, "playing through" might have helped...dunno. Over-use problems rarely get better unless you stop the over-use. They will if the body can possibly compensate. (Callouses being an example of how the body compensates for a minor type of "over-use".) Tendons don't get better unless you quit beating up on them.

Thomas the Rhymer has some good advice, IMO.