It's been almost a month I am Having pain in left chest,it comes and goes.it increases when I press that pain area.and pain also increases when I lift my arm,lay in certain position etc.some times having pain in ribs that increases when I take deep breath.but now left chest pain is coming simultaneously.and I am also having shortness of breath sometimes.i am thinking like iam goin to have heart attack or lung cancer something.i am really afraid please clear my doubts.is it serious?