Posture correction must. Avoid toward bending and lifting weights. Physiotherapy treatment for few days. Muscle stiff is there.

From your description it appears to be muscular back pain. Majority of this is caused by incorrect sitting posture, weak core strength and incorrect carrying of loads. If there is no pain going down the back of legs or no numbness, this most likely represents musculoskeletal back pain.

Piriformis Stretch 1. Lie on your back. ... 2. Cross your left leg over your right so that your left ankle rests on your right knee. 3. Use your hands to grab hold of your left knee and pull it gently toward the opposite shoulder. ... 4. Hold for 15 to 30 seconds. 5. Relax, and then repeat with the other leg. 6. Repeat this cycle 2 to 4 times

Hi looks like it is SI joint dysfunction. Avoid sitting cross leg, single leg standing which will make it worse.

Start with back strengthing exercises it should help you out . Sending you the link for same https://play.google.com/store/apps/details?id=com.backpainrelieving.backpain

Hi u should access ur working posture and try to correct it in guidelines of orthopedic doctor. N physical therapist. Ur problem is related to back spine n. Lt. SI joint. It should be resolved in 3 wks if you take proper care of your health...