I recently went to a cold place. While climbing a hill I felt a squeezing feeling in chest for once. When I finished climbing it went away. I had read that it is a symptom of Angina. So I tried climbing that hill again for a couple of times and also the next day morning when weather was chilled. But I never had that feeling. I also climbed some other hills that day. But never had that feeling. I used to do annual health checkup. And the last one did was 3 months ago. That time echo, ecg were normal. I also did tmt once before 1 year and 10 months. It was also negative and normal that time. Should I be concerned?