I have had this lower left back pain and lowest left rib area, please advise?

I sleep on a thin foam mattress which has given me back issues in the past but just mild discomforting pain. I sleep on the side and my back through the night. Last week for two nights I started sleeping in the other direction (180 degrees change) and I slept that way 2 nights in a row and since then I have had this lower left back pain and lowest left rib area. When I sneeze or cough I can feel the pain. I haven’t taken anything for it yet. When I pulled a door, I could feel the pain in the lower left back again. I pulled the door with my left hand.

Age: 32
Male
Medications: Nothing. Just started taking Aleve right now.