I want on a backpacking trip over Labor Day weekend. We left Thur. and arrived in the San Juan Mtns. of Colorado on Friday. We setup our basecamp and on Saturday we did a strenous day hike of 10 miles going to an elevation of 10,600 feet which was an elevation gain of about 3000 feet. Saturday night I awoke with chest pain that increased when taking a deep breath. However, after rolling onto my side for a few minutes the pain eventually went away. I've experienced this pain each night for the past 5 nights and a couple of times during the day. BTW, I left CO on Monday around noon. I went to my GP today and he doesn't know...he says he doesn't think is heart related since the pain went away when I moved to my side. But he still wants me to do a stress test. Anyone have any thoughts on what could be causing this?