My 2 cents: I had rsi, then I started bouldering. At first I got more pain. The original rsi, but also the 'forearm pump'. But then after maybe half a year the pain dissappeared. Not just the new pain, but the old pain as well.
This is why a lot of what PT’s do is teach you simple exercises to work ALL of your muscles, including those that might not get activated in our day to day existence, leading to problems.
From personal experience: if you have mild pain from past injury/strain, don't give up on trying to fix it. Move a lot, improve your muscle strength and try to stimulate circulation. Be careful not to repeat the injury, but don't avoid the pain altogether (eg. by reducing the amount of movement). It's possible that the pain will improve or disappear, even if your injury didn't heal by itself for years.
(Oh, and go see a physiotherapist a couple of times if you haven't already.)