I Have Being Having Chest Pain And I Am Just Curious

i having being having chest pain on and off for a week or two now it seems like whenever i lay down to go to sleep my chest starts bothering me and my back starts to hurt particularly on my left side. but it becomes hard for me to got to sleep because it feels like i can t breath and that there is a pressure on my chest. has anyone ever heard of this. i looked up my symptoms online and have found something called Pneumothorax. My symptoms are very simliar. Has anyone ever experienced this please help!!! Serious Inquiries and Answers only Thanks!!