Thanks for query on hcm.
Pain in abdomen with back pain
is suggestive of renal stone of that side.
You have to go for urine test and usg abdomen to confirm the diagnosis.
Numb leg,foot is usually occurs in b12,d3 and other vitamin deficiency
Drink more water.Start nsaid
to subside pain.
B12,d3,minerals and other vitamin supplement will be helpful.
Consult your physician for proper diagnosis and better medical management.