Headaches and painful calf-muscle twitch

For the third consecutive week, I've been getting a headache after I get home from the long Saturday run. I turned to friends, ASHA mentors, coach and google-the answer:I was getting dehydrated. I did stop at every water fountain in the park, but I did get thirsty between water fountains, so I decided to carry a bottle of water while I ran. I had one of those fuel belts that I had bought years ago to motivate myself to exercise. So I started stopping to take tiny sips of water every 8 minutes or so. That cured my headaches. 

I had also started getting a pain on my right calf muscle which I can best call a painful muscle twitch. It felt like the more I ran, the more this nerve or thin string of muscle in the middle of my calf would wind tighter. When I tried to stretch at the end of the run, it would protest painfully and I could hardly bear it. I used that as an excuse not to run a couple of weekday runs until I realized that I was only fooling myself. 

Finally, I discovered that if I warmed up and stretched a bit before starting my run, that muscle would not pain as much. It also helped if I stretched my calf throughout the day. I tried writing alphabets in the air with my feet while sitting at my desk at work, like Prutha & Jayashree (mentors) had recommended, and it helped a great deal. But I have a feeling this string of muscle is a troublemaker, and I will hear from it again & again during my training...

I am feeling muscles (painfully) on my legs that I never knew existed. I am painfully aware of my legs all the time- they are always sore.