A couple of years ago, I got golfer's elbow from doing high volume chin-ups (supinated pull-ups). I'm at an age where this kind of thing is common (I've heard of it referred to as "middle age pull-up syndrome").

I tried to ignore it and work through it, but it got worse, and I eventually went to therapy where they recommended the Flex bar. It took more than a few weeks, but eventually it completely resolved the pain. For me at least, it did the job, and it's a lot cheaper than a single visit to the therapist (even if you end up buying multiple "levels" of it).

Nowadays I do my pull-ups on gymnast rings, so these creaky old elbow joints can move freely rather than being stressed by a fixed hand position.