You said the tendon hurts with bb curls? Kind of like inside the elbow area? I know straight bars for curling can aggrevate tendinitis. For me it does so very badly as its beyond a twist of comfort to have my wrists turned that far outward. Try dumbbell/kettle bell curls as it allows you to have a more "natural" grip and range of motion in your wrists. Ez bar fixed the problem as well for me.
Idk about you but I cut curls out of my routine as my pulldowns and rows hit my biceps enough as is. Occasionally I'll do some higher rep/low weight curls for the pump :D
Yep use an EZ bar and try not squeezing the bar grips with your fingers, kinda have a very loose hold nothing else.. Try pressing on the area of pain very hard for about 7-8 seconds before each set, it may take the pain away sufficiently until the next set... Then do it again and so on....!!