Hi @Shan_07 - how long ago was your surgery? Mine was breast conserving surgery as well, with sentinel nodes removed. There is always some discomfort & some numbness with the node removal as it is under your arm & nerves may be affected as well - but as @Blossom1961 says - if it is causing concern, get it checked out. I didn't get the chest pain tho.
Do you have a 'care plan' with your GP? You will be able to see an Occupational Therapist, have physio & even see a psychologist if you need to. Ask your GP about it.
All the best ..... hoping it eases for you soon xx