What Causes An Altered Sense Of Smell?

Six years ago to present: i can only smell food, it smells so horrible and i csn not eat any food because taste is horrible also. I stand on my head, spray Lidocaine in each nostril and then have aprox 45+ min to microwave food (can not cookep brcause of smell) . My body ( shoulders, beck hands etc ) is wearing out . No doctor has any suggestions . I have had all tests, mri-brain tumors, no severe head injuries, only a few sinus infections previous years, none severe, had DNA testing for food and medical allergies. Had results so followed dr. Orders, nothing hS ever improved only got worse. Do you have any suggestions? Thank you This was totalmif 7+ years hard to simplify, hope enough info. Linda F Campbell