In reply to flopsicle:
Q1. At some point hills can be so steep, that walking is faster/more efficient than manageable running. Just make sure it's not a break from running and is still the same level of work -i.e. hands-on-knees fast walking. Once you reached the top of the climb, breaking back into the rhythm of running can sometimes feel like a relief.
Q2. You can only really assess your HR from how out of breath you are, not how tired you feel. Late in a run when you've depleted your glycogen stores, you simply haven't got the energy to run with a high heart rate. Your muscles kill and it'll feel like more effort, but you're probably not out of breath
Q3. don't quite understand...
Strava question: Yep, just make a new segment that's public. The try and get Strava to delete the original segment