Can even light theraband exercise on overstretched upper back muscles cause burning that has lasted for around 5 days. trying to strengthen muscles.

It can. : 'muscle burn' occurs when you exercise strenuously enough to build muscle, and peaks at 24-72 hrs. It is caused by micro- tears in the muscle itself, which leads to the muscle to rebuild. If it lasts for 5 days, it means these micro-tears in your upper back are too overstretched and you will need to avoid mm strengthening exercise for about a week. Do light activities.Restart then every 2-3 days.