early weds morning i woke up with severe pain in my lower chest, right at the base of my lungs, and my sternum, but also in my lower abdomen. it made the pain worse when i lay on either of my sides, or sat up for too long, I rang nhs direct and they said to take paracetamol and the pain should die down, the stomach pain has gone, and the pain in my chest doesnt hurt as much, but it still hurts when i breathe. what could this be?