Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
Your detailed history about pain in
rib cage on left side, cancer
breast surgery that you are free from, stress and
anxiety of all sorts indicate the probable reasons to be as follows:
Most probable cause is
costochondritis.
Secondary of cancer breast in rib is possible and a PET scan can help.
If other investigations are normal then this can be treated in the following ways:
Rubefacient liniment locally.
Strapping over affected part to control movement of the ribs and pain.
Anti-inflammatory medication with painkiller properties.
Local steroid injections or oral dosages may help.
Consult and discuss with your Doctor about the probable disease and management as discussed above.
Hope I have answered your query.
Let me know if I can assist you further.