Tendonitis, especially in the elbow, is most likely caused by tight muscles in the forearms and tricep. I get it really bad from doing a lot of pullups or kettlebell stuff. Try taking a lacrosse ball and rolling out your tricep I bet it will be excruciating haha I know mine hurts like a motherfucker when I do that. Also, taking your opposite knee and gently smashing your forearms will help get rid of all the little knots and adhesions in your forearms that get built up from grip-intensive exercises. Our forearms are the equivalent of our calves and I know I don't do enough mobility/recovery stuff for my calves since I always manage to get shin splints so why not help out the forearms that are constantly in use? There are these things on the roguefitness website too called voodoo bands...they are compression bands that you can use on pretty much any muscle and it will help with recovery. Not expensive at all I've been using them and they've improved my squats, kettlebell press and I don't get tendonitis anymore.