It is likely to be premenstrual tension (PMT) sometimes called premenstrual syndrome (PMS).
Eating a healthy and well balanced diet with lots of fresh fruit and vegetables and cutting out or cutting down on junk and sugary foods and processed foods as well as fizzy drinks can help. Make sure you drink plenty of fluids and especially water.
You may also find Evening Primrose oil helpful. You can purchase the capsules from large superstores or from the herbal shop.
i normally have the same symptoms as you a couple weeks before my period starts, so it could just be that! I never used to get heavy and sore boobs up until about 8 months ago. So it could just be a new symptom.