Does anyone know how to help/cure muscular pain in the lower back?

Low back pain. Most likely you are experiencing musculoskeletal strain in your lower back. Applying a heating pad to your back may be of benefit. Also, taking Ibuprofen or Naproxen for a short time may be beneficial. I discourage lifting objects over 20 pounds. If your symptoms persist or worsen after a couple of weeks, I would recommend that you see your primary care physician or neurologist.