Trying to improve my running

Humbled today. I don't know why but the run this morning really kicked my but. I have done this run (Wasson peak) over a dozen times and had been getting faster and faster and feeling really good about it. Today though. I was about 10 minutes slower than my recent runs and felt tired through the whole thing even coming downhill was really hard. Oh we'll I guess I couldn't continue to get faster every run. Time: 1:31:18 AP: 11:58

Local trail run. I had a lot of chest pain at the first of the run. I think it was GI in origin (I had heartburn last night). It really made the first mile super slow I felt like I couldn't even stand up straight. I loosened up after a mile or so. I still didn't feel great for the whole run. AP: 10:11.

Ran up Wasson peak again today. The first mile was pretty painful, but I felt better after that. I was still slower than I had been a couple of weeks ago. I was even a bit slower than on Monday. Unfortunately I fell with about a half mile left to run. I was able to get back up pretty quickly but had to hobble through the last bit. After the run was done everything really hurt. This is the first time I have fallen in almost a year. I better not make this a more regular thing. AP 11:46. Time: 1:32:59

After getting hurt yesterday. I didn't think I was up to going to far. I just did some slow trail miles on the trail by the house. I still had the same problem I had earlier with weird chest pain at the start of the run that went away in the first half mile or so. Not sure what that is about it has happened twice this week. My body was super stiff from the fall yesterday, which surely wasn't helping. slow miles AP: 10:00.

Another trail run by the house. the week continues to be a really hard week. I don't know what is wrong hopefully it is just being tired. AP: 10:21.

1st run: This run was the worst run of the week. I did this while at work. I was so tired. It was so hard tog et started. I was having chest pain at the start and also feeling really short of breath. I felt so bad I hooked myself up to the POx machine at work my HR was in the 40's the POx was 100%. I started to worry about my having a heart block or some kind of problem causing me to be in this funk. I was only able to do 3.11 miles and the AP was 9:41

2nd run: So after stewing on the terrible run all  the rest of the night and during the day when I couldn't sleep I ran again at work on Saturday night. I had some difficulty starting just like all week. I had some chest pain it did seem to get better a little quicker than prior. my ave HR for the first mile was 170. after that it seemed to slow down to normal 140's and best of all I felt fairly normal if a little tired. my time was better I went for 4 miles w/ an AP: of 8:49 still slow but at least not too frightening. I may try and get an EKG or see a Dr if this doesn't get better.