What Are The Side Effects Of Cortisone Injections?

I have had several cortisone injections in my right shoulder for what was originally diagnoiseed as bursitis...the pain is still bad however it seems to be affecting my right forearm more. I don't see my doctor again till next week, last injection was a week ago...could the bursitis be related to something more?
I work as a support worker in disability and have attempted to continue working, the pain is increasingly causing me to find simply tasks difficult including driving, cleaning and even brushing my hair