<qa>  What is the main cause of shoulder pain?Shoulder pain is highly prevalent in the society. The role of muscle tissues in this pathology has received increasing interest. Some studies have proposed the role of myofascial trigger points in this population. The purpose of the current clinical trial is to compare the effects of physiotherapy treatment consisting of an eccentric exercise protocol versus the same physical therapy program plus the addition of trigger point dry needling TrP-DN on pain and function in patients suffering from unspecific shoulder pain. 