Hello and Welcome to HCM,
Thanks for writing to us.
Your pain seems to be mechanical in origin due to bad posture and carrying heavy weight.Mechanical back pain
implies the source of pain is in the spine and/or its supporting structure. The surrounding muscles and ligaments may develop reactive spasm and pain.
The treatment usually involves rest with pain killers in combination with the muscle relaxants along with good physiotherapy
You can do a hot fomentation and apply a local analgesic
gel on the area to relieve the spasm.
Hope this helps you.
Wishing you good health...
Dr Saurabh Gupta.