What Causes Left Clavicular Pain On Taking Deep Breath Or Sneezing?

I have been having severe stabbing pain in my left clavicle for weeks it had progressed to my left upper chest and sometimes around my left arm pit. I have been in the ER 3 times in the last 3 weeks with diagnosis of pulled intercoastal muscles, pleurisy and maybe a touch of pneumonia. I have had a CT to R/O PE which was neg. I am currently on a tampering dose of steroids and was given dilaudid to help me sleep which only makes me stay up itching all night. I thought this pain was going to get better when I had a day of relief when I started on the steroids now it is back full force in my left clavicle again worsening when I bend over, take a deep breath and sneezing brings me to my knees with pain. When I sneeze I cannot even take a slight breath without repeating stabbing. Please give me some advice I can't take this much more.