Lower and Upper back pain that is caused by straining yourself lifting heavy objects etc usually resolves itself within a day or two without any treatment.
If you've rested for at least a day or two and taken pain relievers and the back pain still persists or gets worse then going to urgent care or the emergency room would be a good idea.
Also if the back pain comes along with numbness or weakness or pain that shoots down the leg along with the back pain then that is not a good sign and you should go to the emergency room or urgent care.
But if it's just muscle strain and the back pain is not too severe then the back pain should easily go away with a heating pad, hot bath, and pain relievers as well as rest.