3year child complaining about lower back pain

Dear sir

My three year child make a jump over the body of his 10year old sister during play past two months ago


After that sometimes he say pain in back again two minute later he becomes normal and play


But 4 days before he have a cough doctor gives him antibiotics after taking antibiotics cough is normal and a mucus containing stool daily 3 times then i give him zenflox oz after that he doesmot go for latrine and make a complain about back pain in 15minutes duration i use fast relief ointment but no improvement yet in his pain


Plz advise

He have little appetite

In past in his stomach threaded white worms in that case doctor give him cina30


Plz advise someone

Thanks