A few comments:
- First and foremost, it sounds like you're suffering from what I call TFFFS (Too Far, too Fast, too, Far, too Soon). The issue here is that the muscular and the cardiovascular systems develop at a faster pace than do bones, joints, ligaments and tendons, The pain in your lower legs is a very common malady for folks relatively new to running and a pretty sure sign of TFFFS.
- Second, stretch during (if necessary) and after your run, science has proven quite convincingly that stretching prior to a run is counterproductive.
- Third, using NSAIDs like Ibuprofen can make things worse, much-much worse.
Long story short, were I your coach I'd tell you to take several weeks off, and then to start your running again at a vastly reduced paced, say no faster than two minutes per mile slower than your current pace. When you get to the point where you can run slow for a few miles with no pain, then instead of going faster, go further, and when you've reached six miles or better per slow run, then, and only then, should you think about gradually increasing your pace.
A word of caution: I've had shin splints (which is what I suspect you're suffering from), and I've known lots of other runners who've had them as well, and it seems that once you've gotten them, you are much more susceptible to getting them again. The only way I was able to get past this issue was to take a good long while off, like several months, and then to build my mileage base up very-very slowly. Maybe it's just me, but I have over 1,500 miles logged since I restarted my running in mid-April, and I'm still not sure I'm ready for upping my training pace.