Hi, I Am 16 Years Old 5'4 And About 95

Hi, I am 16 years old 5'4 and about 95 lbs. I am a cross country runner and have been for the last 3 years. This last season I fought knee pain pretty much the whole season and wasn't able to train much. We thought we had it fixed but it came back so I got told after state to rest for 6 week by a chiropractor. I resently started back to running and my knee still hurts but no one can figure out why. Can you help find the cause and treatment? I don't want to make it worse.