If you're feeling that tight, tense, achy sensation in your back muscles, you're probably one of the many victims of back pain. There are many reasons why people experience back pain, and it's usually from repetitively overusing your muscles or pushing them to perform too much physical activity that they are unprepared for.
The typical activity-related causes include work-related stress, yard work, heavy lifting, new exercise habits, sports activity, and even house work can all strain the muscles in your back. But don't worry, these strains are usually only temporary.
There's also a more scientific reason for muscle pain, the strenuous activity causes an accumulation of lactic acid, which is known to cause pain and soreness in muscle fibers. It takes your body some time to metabolize lactic acid from your muscles, which is usually why massage therapy helps - it kneads out the build up.
Get the full story here: Sore Back Muscles