It's an unfortunate fact of life that we're all occasionally forced to take time off from our typical exercise routines. Even more unfortunate is how difficult it can often be to restart your training and get back to your previous level.
Restarting a running program can lead to greater muscle soreness than with other aerobic activities simply because of the impact forces you experience with each foot strike. As a result, you need to be extra cautious and conservative in order to minimize muscle soreness and reduce the risk of injury. Start on your way back by running every other day and separating your running days with a day of
After a week or two of running every other day, you can start grouping your running days together; run two days, take a rest day, run two days, etc. In the first week, your runs should be short, only about 15 minutes. The second week, bring them up to about 20 minutes, and then the third week go for 20 to 30 minutes. By this point you should be past the point where muscle soreness will be an issue and you can increase your weekly volume and intensity at the safe level of 5-10 percent per week.
Good luck getting back on track!