Some researchers are now looking into the possibility that one of the things that happens is that the nervous system becomes hyperactive to pain. This means that it takes a much lower stimulus to provoke a pain interpretation in the brain. Instead of a deep pressure to evoke a pain sensation, it only takes a light pressure. Instead of a lot of a muscle activity to make your muscles feel sore – it just takes a little bit of activity. Your brain is “primed” to feel the pain.
Additionally, nerve pathways are “learned” pathways and they build reflexes or associated pathways. Just as an athlete practices and trains their muscles to respond in a certain way – your body and nerves “learn” to react in certain ways. The longer time you have pain – the body (muscles and nerves) learn to react in a particular way and develop into bad habits. We have to “re-train” both your nerves and your muscles to react in different “good” ways.