Hi, Welcome to Health care magic forum.
As you describe, the left breast is bulky, and tender, around the periods.
Chest appears to be tender on left side , The reasons may be the chronic chest infection
, esinophelia,infection in the breast,or gastric irritation.
I advise you to consult a physician for diagnosis and treatment.
I usually prescribe to my patient with such symptoms omeprazole
, and antasid gel.
Wishing for a quick and complete recovery. Thank you.