asa-ren week has started

This week, I have to run in the early morning while sunrise. That's good I don't need to run in the cold evening, but it's hard to wake up earlier some times, it's hard to do speed session because body could n't get warm up easy to run at fast pace as my coach expects my speed.

Monday, 5th in the morning.
Just went to zenpukuji park as usual for very easy running, it was fun but chilly.

monday's efforts:
mil: 5km
time: 27:52
avg HR: 148-76%
avg: pace: 5:34/km
cal: 215kcal
beginning time: 7:43am
location: zenpukuji park

Tuesday, I was supposed to 14km moderate running before work.
I built up the pace lately from 5:30, 5:15, 5:10, 5:05... and finally got up to 4:30 in the end for only about 2minutes. After that paced down to around 5:30.
Why my heart could beat even run in the slow pace as 5:00/km? Does my heart have any problems?
Should I go to see a doctor??? Just I want to be a little bit fast runner more...
Because of my half marathon splits, I'm really interested in running in my hometown Miyagi, there is a Sendai Inter'l half marathon that will be held by the Japan association of athletics federations on May 13th in Sendai, I just have signed up already to get good result that I want to get.

tuesday's efforts
mil: 14km
time: 1:17:14
avg HR: 154-79%
avg Pace: 5:29/km
cal: 601kcal
beginning time: 7:31am
location: via zenpukuji park, ome kaido, mitaka station to Inokashira park
weekly mileage: 19km