What can i do for this pain in lower back, please advice?

Pinched Nerve/Muscle: Most times back pain that is sudden onset will resolve. You should use anti-inflammatory meds like ibuprofen, aleve around the clock and even tylenol (acetaminophen) to help. If this does not resolve you should see your doctor for a full evaluation. If it still does not resolve, I would recommend to see a spine specialist for a full evaluation and testing. You may need to get an MRI to see inside the spine.