What are the best teatments for backaches?

Depends. Backaches is general term. What are the associated symptoms of your backache? One has also to identify the causes of the backache. Is it due to your lumbar muscles or due to degenerative or arthritic conditions. Options range from conservative approaches such as physical therapy, massage, tens. Drugs like nsaids, non opioid analgesics , interventional procedures help, surgery for serious coditions.
IBUPROFEN OR. Tylenol (acetaminophen) and stretching. See doc if no better or stretching makes symptoms worse.