When suffering from a tendinopathy (e.g. an epicondylitis), one often faces the dilemma between exercising to regain strength, stretching and resting. How to decide what is the most appropriate action?
Purely anecdotal, but I've never seen good results from pushing tendinitis (and bursitis, and really any connective tissue inflammation). Decades of (amateur) athletics have taught me that the magic to treating tendinitis is to identify it early and stop aggravating it.
A little bit of tendinitis is a lot easier to work through than a lot of it.
In the "good vs bad pain" continuum, tendinitis is very much on the "bad" spectrum. In large part this is why proper training spends so much time ensuring that you don't develop overuse injuries (such as tendinitis) since it is so debilitating and can easily sideline progress for weeks.