I think you are in good shape considering you just started training less than a month ago. One issue might be that your training plan is a little over-ambitious, going from about 7 miles/week to 25 miles/week in barely over a month is a big jump. You can do it, of course, but not without some growing pains. From my experience, I would say that in a long run of 10+ miles it usually takes me 2-3 miles to get fully loosened out and I do not reach peak speed until the second half of the run. So starting out slow is normal. One common solution is to start your workout by slowly jogging 1-2 miles and then stop and do your stretching. That might help a bit, but since you are going so quickly from recreational running to a 1/2 marathon, you probably are just going to have to suck it up on days that you do feel 100%. You will see gradual, steady improvement with time. Best of luck with the training! Edit: Another thought: it is essential for recovery that you eat/drink something within 15 minutes of finishing your run in order to aid in recovery. Ideally something high in carbs like gatorade, fruit, or a granola bar, or all of the above.