Brief Answer:
Need more information.

Detailed Answer:
Hi:

Thank you for your question

I have few questions, if you can answer them for me please, it will help me in making the diagnosis as many conditions can give similar symptoms.

1. Do you have the pain in the tail bone area (coccyx) or just over the right buttock?
2. Can you sleep on right side of hip?
3. Do you have any back pain?
4. How long you have had these symptoms?
5. Any recent hip injection or injury?
6. Do you have sitting job?
7. Any numbness or tingling or pain radiating down the right leg?
8. Any pain on pressing outside of your hip?

Please do write back to me with the answers so that I can guide you better.

Awaiting for your response,

Regards

Regards

---

Brief Answer:
soft tissue inflammation

Detailed Answer:
from your answers I can see that the symptoms started following the hip injection, which might be the cause for inflammation of a muscle in you buttock (most likely piriformis)

other soft tissue inflammation can give similar symptoms like inflamed tendon or inflamed bursa around one of the muscle.

my advice is to use anti-inflammatory gel or cream over the most tender part of your buttock and use soft cushion when you set.
physiotherapy may help.

if no improvement then you need to get further investigation such as x-ray or MRI scan of the pelvis to confirm the diagnosis.

hope you get better soon

---