Achilles Tendonitis

[anch]

I've been suffering wth a problem with my ankle for about 6 months. The majority of the time its fine, I can walk and run on it with no problem. I play football and again the majority of the time its not a problem. Its times like when I got out my car and I caught my foot on the door cill as I was getting out, and instantly I got a bad pain all around the top of my foot, in my heel and a shooting pain going up my shin, I get the same pain if I fail to my a good contact when kicking a football, the pain last about 10 mins, then my ankle feels fine when walking, but a little tendor to touch around the front. But most of the time my ankle is fine although it sometimes feel like it a little bit weak. The only previous problems I have had was an ankle sprain about 10 years ago which took 6 weeks to heal. Anyone got any ideas?