I did have that issue as I train very high volume with little rest. I found my tendonitis was more due to the movements I was doing and the limited range of motion I was using. This was especially true for my shoulders.
Always had tight rear Delts and regularly heard popping when I rotated my shoulders. I started doing lateral raises with cables (which started painful). Chest fly's and butterfly's with increased ROM ,and behind the head lat pulldown.
Sounds ridiculous but I kept logs and that is the only change I have made in the gym.
Reducing inflammatory foods has helped also.
Stretching has never worked for me but increase ROM while under weight has worked. I hate missing days at the gym, and taking rest days is like pulling teeth.
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