I may have sacrioliac ligament sprain. i waken from sleep with a strong dull ache in my left hip to knee. sitting is painful. also sciatica symptoms.

Neuromuscular: The treatment includes physical therapy with traction and lumbar stretching exercises, muscle relaxer, analgesics, medications like Neurontin Lyrica (pregabalin) Cymbalta or amitriptyline. Pain clinic and acupuncture are last resort prior to consideration for surgical intervention. I would consider repeating the MRI if not recently done, and get neurological or pm&r evaluation for emg.

Sacroiliac (SI) pain: Is typically with standing, walking & running as it is weight bearing joint & better at rest. More common issue would be from the spine. A hip problem could also be a cause but sitting suggests more of spine related issue as 4 times body weight is applied across the discs of the lower back with sitting. A hip problem would be also painful with weight bearing, not sitting but could ache at night.

These: Go hand in hand. The Sciatica has resulted in weaker muscles in the buttock and leg resulting in stress at the sacroiliac joint ligaments. You need treatments that are tailored to treat both the sciatica and work on tightening the ligaments around the SI joint.