Fell a few months ago had back pain for about two weeks, it's now returned and seems to get worse when standing?

X-ray: Start with an x-ray. If normal or no significant finding, conservative therapy. If persists, mri.

Soft tissue pain: The most common cause of back pain is sprains ANS strains of muscles, tendons and ligaments. If your pain is localized and does not radiate down into your leg and foot, it is most likely not from your spine, discs, or squeezed nerves. However if your fall was severe you could have damaged structures in your back and pelvis. If your symptoms do not improve or get worse, you should have a physical.

Need an evaluation: If pain has returned few months later then it needs to be evaluated by your physician. Normal ache from falling should be resolved by now. Possibly a fracture.