Could it be a sign of pregnancy if you normally have breast soreness the week before your period but this month you have not and your period is due in 5 days?
Sometimes a womans breasts may be tender on her previous period but on her next period they wont be tender or painful. This is a commonn occurance. I wouldn't suspect pregnancy unless you have any other pregnancy symptoms. If you do then see your doctor for a blood test. Take care.