I don't know if you can "sprain" your spine, but your back is a complicated structure. I would advise you to give it a few more days and see if rest helps. I would also advise using the meds, and icing it for a bit, and see how it responds. I don't think a chiro, at least while there is probably swelling, is the best answer, but again, I'm far from an expert, just some poor schlub who had a couple of herniated discs, and has had back pain off and on for my whole life.