Sir, my father had a back head long fall and after 3-4 days his burning sensation in lower rib cage persists?

Sounds like a contusion which takes a week or two th get better. Use moderate heat locally three times a day . If not better in 10-12 days see an MD to rule out a fracture.

An elder adult is at increased risk of injury from any trauma, and if there are persisting symptoms after a fall, muscular injuries, skeletal injuries, and/or internal organ injuries all remain possibilities. He should see his Provider or an Urgent Care Provider for a screening exam and to consider if imaging or other tests are indicated.