What Causes Breathing Difficulty And Headache?

Hi, I have had a feeling like I cannot take a deep breath the last couple days and this morning I woke up with a pain in the upper left side of my chest. I have also now developed a slight headache and have had a weird gushing feeling in my head. I don t know if any of these symptoms are related. It all sounds kind of silly. My pulse and pulse oxygen have been fine. Thanks for your help!