I Have Been Urinating Blood Off And On For At

I have been urinating blood off and on for at least a year. Other symptoms include fever chills, burning, pain, and frequent urination .Thus far no diagnosis, No infection, no cystitis, no bladder cancer. I have had cystoscopy, urinalysis and ultra sound of pelvic region. A tiny lesion was found on my left kidney that MD reported to be insignificant. The blood in my urine was the darkest red it has has been and lasted 3 days, then went to pinkish color. What could be the next step.