After six months of pain I'd expect a few weeks rest to be on the agenda. Taking the long term view is wise.
I'd definitely go to a physio as my first port of call. The usual pattern is: rest and manipulation for a couple of weeks while starting very light strengthening or stretching; then gradually more strength and stretching work; once pain is gone and progress has been made on the key movements, a very gradual return to running. I'd think about biking, swimming, ,or climbing to maintain fitness in the meantime. Could also consider pilates or yoga as a stop gap especially if your posture is less than perfect: quite fun and a good way to prevent various possible future injuries
Worth considering your approach to running to see if there's anything you could change in future once you're better. E.g. Over-striding would cause more heel impact. Inadequate warm up is a common contributor to injuries. Old shoes, or ones that aren't suited to your gait and alignment. Not mixing up the paces and distances you run is another common issue, an extreme example is a friend who always ran the same route and tried to PR it every time(!). [sorry, just re read you post and the middle 2 obv don't apply]
Post edited at 11:05