Does Tenderness And Soreness In Chest After Having Protected Sex Indicate Pregnancy?

Hello, my name is Ryan. I started having protected sex on Sunday after the Superbowl. My girlfriend has been experiencing tenderness/soreness in her chest since Thursday of this week and felt nauseous only in the morning on Wednesday (after taking 3 pill for a cold), would you consider it to be an early sign of pregnancy as to consult a doctor or a normal menstrual cycle (which is expected in a few days). I know that Plan B works without 72 hour (however sperm is still alive until 7). Please give me advice on what you think she has or I should do. Thanks