welcome to hcm,
you might be experiencing muscular spasms which could be due to reasons like
3. if pain is going to the lower side of the stomach then we need to rule out a urine infection
4. if the pain is going to the legs with numbness
then you need to rule out sciatica
, slipped disc
you need to be investigated for the above causes, to know what is causing the pain
you can take painkillers to alleviate the pain
if you are not using firm matteress then you need to change it.
you need to have your back in alignment with the chair when sitting to avoid strain on your back
dont be lifting heavy objects and bending alot.
would suggest visit a specialist to get to know what is causing the back pain
hope have answered your query
get well soon and takecare