What Causes Pain In Chest And Shoulder Blade With Burning In Breast?

hi I have been having chest, shoulder, shoulder blade arm pit and burning in my left breast for about 8 months now. my obgyn thought that maybe it was from breast feeding for and pumping for 8 months but I have had 2 mamo 2 ultra sound and a breast mri. nothing. and I do pain management too still in pain.