Any OTC med replace methocarbamol 500mg? Lower back pain, X-ray's 4 month ago, dr said I need this. Pain back do I need go back dr or can take OTC med

Return to doctor. If the doctor has determined that you are best treated with prescription methocarbamol for your back condition then, it is much wiser to return to the doctor if things are not working out instead of self medicating with OTC meds and allowing your condition (whatever's causing the pain) to progress unbeknownst to the doctor. That would be a classic example of exactly HOW NOT TO TREAT YOURSELF.