Suggest Treatment For Severe Joint Pain

hi my mother is suffering from severe joint pain so much that she is not able to walk even although the reports for arthitis were negetive 3 years before she went throgh a surgery of removing tumour and uterus and after that the problem started and also during surgery an injection was injected in her back and after that she always have back pain whenever she takes any pain killer her body gets swell and she starts vomiting she is 45 years old i don't know what to do