Pressure in chest

Patient: Good day.My name is Grigor.I am from Bulgaria.In the last month I started feeling pressure in my chest. I feel like I am having air deficit, but thats not the case.I feel like my chest is expanding even when I don’t bread.I started weight training late July. I also started swimming a month ago, 2 days a week. My trainer wanted me to perform breathing exercises. I don’t take any kind of supplements.