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Right now you need to get that inflammation down. That's your first priority. Rest, ice, compression, elevation.
I fought with that 'injury' for a long time, through years of track and field, road racing, and triathlons. It was always the worst after I took an extended period of time off and tried to come back too quickly---or if I was overtraining.
Good shoes are a must, and you need to be fitted by someone who knows what they're talking about. I'm talking a specialty running shop, not the high school grad at Foot Locker.
Consider orthotics. There is no commercial insert that will provide as much comfortable support as a set of custom orthotics.
Stretching is a no-brainer. Warm up, stretch, cool down, stretch. The post-workout stretch is often neglected.
Post workout massage. Fill up some small dixie cups with water and stick them in your freezer. Grab one after a workout, peel the cup back, and use it to massage the area.
Do not train hard on hard surfaces. If you must run on the street, do your long slow distance on the street. Avoid high intensity work on hard surfaces like asphalt/concrete. Do your tempo/fartlek runs on trails, grass, packed dirt. Do your speed work on a rubber track. If you find yourself sprinting on asphalt, you are asking for an injury. I would avoid running regularly on sand due to the absolute lack of stability it provides.
You may have to notch back your mileage/intensity and build it back up again. Cut your mileage and increase it very slowly. Do not increase weekly mileage by more than 10% per week---and that number is assuming that you're injury free!
Cross train. Don't run every day until you've built a solid base and your body is ready. Cycle, swim, row, etc.
Strengthen your lower body. It's somewhat rare to see someone doing leg exercises in the gym. It's even more rare to see anything beyond the usual squat, lunge, leg press, curl/extension. Google calf/shin exercises.
This all worked for me. Best of luck and train smarter, not harder!