Heel/feet pain while running slower
I'm 27M and have been running since past 7 months. I finished by 10k in 70 minutes (my best) and got a running watch as well since I got into the habit and can track my heart rate
My runs used to feel easier but when I see my heart rate it easily crosses zone 2 (I did the karvonen method to get my accurate zones and not by 220-age)
So to keep keep myself in the lower heart rate (under 163), I am tending to run slower which is causing heel and feet pain especially I can feel the load near the Achilles tendon
Last 2 runs I decided to just go by feel and not look at the zones, then my average HR after a 6k and 7k run is around 169 (upper end of zone 3). There was no leg pain but In between these runs I had to just stop and walk just to get my heart rate down a little.
I don't know how to move further in my plan as I am feeling lost and wanted to seek some advice from the community. I am trying to do my first HM maybe early next year. I know I can do that but I just want to do it injury free as well as not overtrain myself by always running in zone 3 and zone 4.