Thanks for writing in,
Seems you have sustained acute muscle spasm due to lifting weight.
Continue those medications. But rest to the back is very important. Always lie on hard surface while sleeping. Avoid prolonged sitting and leaning forward. Don't try to bend your back and lift any objects. Rather sit down and lift the objects.
Additionally you can a course of Interferential therapy ( Physiotherapy
) to your back along with hot water fomentation. These measures should decrease your pain and make you comfortable. If the pain persists even after a week inspite of all these measures or if there is pain radiating down your legs, then you need to consult your doctor. He might advise you to go for a Xray or MRI
Get well soon.