What Causes Painful Pricking Sensation In The Lungs Upon Breathing?

Hello, so I have an interesting one that my local doctors are calling medically un-explainable I have been having random stabbing pains like millions of needles in my lungs when I breathe, sometimes the episodes last anywhere from 3 mins to 3 hours and the longer they are the more painful they are. Sometimes the short ones stay in one small region and the bigger ones are my entire chest. This has been happening for over two years now. I am going to be a mom in very soon and I would like some answers before that. The larger pains literally put me into tears and I do not want to move, as moving seems to make it worse. I do not think it is caused by stress because I can be lounging at home on the sofa and then it just hits me out of nowhere. It does seem to happen more when there is smoke in the air or the air is really dry, but it has hit when I’m walking around town in the cold (-15C to -30C) or walking/riding my bike in the summer time. I would really like to find out what is wrong because it is hard to do anything when it happens.