1991 had back surgery on l 4 l 5 disk was great for many years. in the 1 year i am having major pain in my right hip pain is going in to the knee?

Pain Recurrence: Pain can recurr from disease progression at level above and below. An MRI scan with & without contrast can help find the cause.

Could be recurrent : Disc issue above or below the disc you had surgery on at the l3-4 level or l5-s1 level. Could also be some arthritis that is setting in status post surgery 22 years ago. Regardless sounds like you have recurrent sciatica. I would check with your doc and get on nsaids and back exercises in the meantime.