Hopefully my elbows will stop this soon so I can get back to exercising.
If the pain is very localized, sharp, and acute during activity and less so during rest then yeah you have the onset of tendinopathy. Coming from experience, if this truly is what you have (could be other things), stop doing pull ups. Now. Rest for a month or two, and PT your arm back slowly. Tendons take a considerable amount of time to heal and repair, a fact I sadly had to learn three times before finally understanding.
Could be something else, so a doctors opinion is warranted. But if some tendinopathy is present, stop use on it immediately.