I have just had time off after having inflammed achillies.I had two weeks rest then went out on a short run but ended up at square one again,this happened repeatedly.I eventually got frustrated because I didn't know how to start running again!
Saw my GP who is sports injury trained and he gave me a return to running programme.As an example for the first week you start with a 5min walk then a 3minute run followed by 1 minute of walking,this is repeated 5 times then finish with a 5 minute walk.You repeat this 3 times in your first week.The run should be a gentle jog.
Each week you increase the running time and reduce the walking time and if things still feel sore/hurting you stay on the same training pattern for a further week instead of moving on.
If all that makes sense,I hope it helps!!