I love pull/chin ups, they are the mainstay of my workout.
My gym has a lifestyle thingy and it has four main grips and I rotate around the grips. I normally do at least 100 a day. A couple of months ago I bought a dipping belt and started adding weight. I weight about 80kg and add now add 12 kg to the belt. Recenty though I've developed pain in both my elbows, chin ups are worse than pull ups. I quit the belt but I still have pretty severe pain.
I'm thinking of taking a supplement of some kind, any suggestions?