my right ankle is hurting after a run?

so i've been running alot this year, and i've noticed that my right ankle "cracks" or "pops" often when i'm running. it occurs at the back of my ankle (very near the Achilles tendon). this has gone on for about 4 to 5 months. today i noticed that my right calf hurt on my 7.5 mile run. it was tight, and my ankle was "popping" also. about an hour after my run, my ankle started to hurt, so i tried massaging my ankle and my calf, but that didn't help. i'm noticing my ankle when i walk now, so it's kind of worrying me. i'm on a cross country team, so i've been running about 6 or 7 miles per day since the beginning of june, and before that i was on the track team. do you have any ideas on what the problem is (if there is one) and do you have a way to fix it? i'm going to ice it tonight.