Hi, my 16 year old son have been urinating blood for about year off and on with clots sometime with lower stomach pain and back. He s had kidney biospy done, culture done, sweep of his bladder , scoper of his bladder...you name it he has had it done and nothing has been found. We stopped him from taking Ibprofen for pain after reading that it causes bleeding . He s currently taking singular for allergies, has a asthma inhaler for asthama along with flovent when needed. He has had no trauma to his kidney or stomach. Please help.