Weakness and pain in limbs post treatment.

Hi,

My father was diagnosed with stage-3 Colo Rectal CA.

He went through Radiation->Surgery->Chemotherapy and all these treatments completed in March 2021.

He physically looks better after gaining muscles and strength but complains about weakness and pain in limbs and shoulder muscles.

We dont have a reason for this pain in limbs and shoulder muscles but I want to know if any one knows any remedy for this pain.

Administered Vitamin injection and multi vitamin tables which reduced his pain but negligibly.

Any information about his will do a great help.