Leftside chest pain/shortness of breath

[BackandChest]

I have suffered a L4/L5 & L5/S1 fusion because of torn disks, yet I still have constant pain.  I have pain on my left side chest/shoulder, lower left ribs especially, as well as breathing problems.  I do not smoke, I am 24 years of age, asthma/meth test, ekg/heart scans, and scan of my spine(even a Total Body Bone scan) have been performed and came back fine, and I am having a neurostimulator implanted on Wednesday for the lower back pain.  I am still concerned with the left side/shoulder/neck pain I have, I exhibited numbness on my left side if I lay flay on my back, and find myself unable to breath.  Laying on my left side is torture.  
It has been two years last June since I first was injured, and I still exhibit the pain in my chest.  When I first was injured I felt tearing in my chest and even to this day I experience pain if I lift my arms.  I do not know if it is Pneumothorax/collapedlung since I am 6'3'' tall or what else it could be.  I am on anti-depressants, clonazepam, ultram, tramadol, and Naproxen Sodium.  Any ideas of what could be cause this pain in my left side?  It is destroying my life and I'm getting tired of all the guessing.  I can only stay up for a few hours then I must lay down because of the pain and fatigue associated with it.  I have been diagnosed with Failed Back Syndrome by my Worker's Compensation and am using my regular insurance now, hence the neurostimulator and psychiatric help.  But any help at this point, may be a life saver.

[BackandChest]

Also I am 6'3" and 180 pounds.  I am not over weight by any means, blood work is fine in reference to gall bladder.  I have still have a well toned body, rarely drink, don't smoke, eat healthy and don't understand why this pain exists, I'm a bit scared to be frank.

[BackandChest]

I am also scheduled for a Cardiac Pulmonary Stress Test in about a week.