Im 25 years old female, had delivered a baby girl 5 months ago. I'm having severe back pain for the last 2 months. Now I'm having deep severe pain on the left shoulder and the full hand. Also the center of my chest is paining a lot with fast heart beat for the past 3 days. I fell down out of giddiness a couple of times in last few weeks. Why all these are happening? Any serious issue? Pls advise.