44 yr old male. for 2yrs constant pain between bottom of right shoulder blade and spine. i weight train 4 to 5 days a week. muscle or something else ?

Most Likely: A muscular problem. Since it is chronic, imaging of the spine is appropriate to include x-rays and mri. These may not show much more that normal degenerative changes. If the pain is wrapping around the chest along the rib then there could be a nerve impingement. Good physical therapy and dry needling could help. I am sure you have been to the doc about this problem by now. If not, then go.