@IamDeablo Tendinopathy, or tendinosis, is degeneration of the tendon. To oversimplify matters, it has been damaged beyond its immediate recovery capabilities, then damaged again, partially healed, and the process is repeated. Each cycle weakens the tendon.
This only tends to resolve through strengthening of the tendon, which means loading it. @AntC is spot on here.
The general rehab pattern seems to be isometrics, then eccentric only, then heavy slow full repetitions, then finally explosive work. Generally exercises that compress the tendon should be avoided until at least stage 3. The exact protocol will vary according to the affected body part and needs to be prescribed by a physio or similar.
You should also be assessed by someone who can see if weakness elsewhere is disproportionately loading the affected tendon. For example, it’s common to get people with proximal biceps tendinosis (which presents as pain in the front of the shoulder, usually) to work on the muscles in the BACK of their shoulder and in the lower traps.
You may need to ease up or stop the initially aggravating activity for a while. There’s some evidence that shockwave therapy speeds things up but it doesn’t work on its own.
I’ve worked through bicep and patellar tendinopathy (both non cycling related) this way and am just getting over some (cycling related) high hamstring tendinopathy. The loading process works, though it takes 3-6 months if tendinosis is established.
You might also want to consider seeing a physio who specialises in cycling. If you’re in the UK, Dan Boyd (ex Movistar physio) is very good.