To stretch your quadriceps at the hip, the idea is to do the opposite movement to flexion, i.e., extension. You can perform extension moves at the hip while standing, lying on your side, lying prone (on your stomach) and kneeling. Even basic stretches done at a pain-free level where you can feel a small bit of challenge, and that are held continuously for approximately 30 seconds may translate to better posture and less back pain.
A diagnostic SI joint injection may be performed to confirm the cause of pain. The SI joint is injected with a local anesthetic and corticosteroid medication. The injection is given using X-ray fluoroscopy to ensure accurate needle placement in the SI joint. Your pain level is evaluated before and 20-30 minutes after injection, and monitored over the next week. Sacroiliac joint involvement is confirmed if your pain level decreases by more than 75%. If your pain level does not change after the injection, it is unlikely that the SI joint is the cause of your low back pain.
A sedentary lifestyle can lead to having weak and tight hip flexors as they are always in the shortened position. Tight hip flexors can lead to a limited range of motion, poor posture, lower back and hip pain, and even injuries. These muscles need to get a workout when you are standing and doing movements such as raising your leg to climb stairs, run, or ride a bicycle.