Hi,
The pain you are experiencing in your right side and back could be caused by a variety of factors. You may have suffered a 
muscle strain or sprain due to the fall. Another possible cause could be a 
contusion or bruise on your right side or back. Additionally, you may have injured your lower back or the muscles surrounding your spine.
If the pain is severe, it is recommended that you seek medical attention immediately. Your doctor can assess your symptoms and perform a physical examination to determine the cause of the pain. They may also order diagnostic tests, such as an X-ray or MRI, to evaluate any potential damage to your bones or 
soft tissue.
Treatment options for pain in the right side and back may include rest, ice or 
heat therapy, over-the-counter pain medication, 
physical therapy, or other medical interventions as needed. The specific treatment approach will depend on the underlying cause and severity of your symptoms.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Priyanka, General & Family Physician