Dear Manon, Breast pain is usually associated with a
benignBenign ear cyst or tumor
Benign positional vertigo (non-cancerous) condition. The immediate cause that comes to mind is some type of injury to the breast. Sometimes breast pain is associated with hormonal variations and is called cyclical breast pain. A medical professional would take your medical history, evaluate the history of your breast pain, and perform a physical exam.
As to when to seek medical help, that depends, you would want to discuss this at your next physical exam. If you don’t have one scheduled or if it is many months away you may want to schedule something in the next month or so. If the pain continues, worsens or you have other symptoms see someone sooner.