You sound EXTREAMLY similar to my brothers problems. He has the same issue, and his body in trying to compensate for pain and incorrect motion has caused him to start developing arthritis in his knees, so now he has knee and achilles problems.

I think initially his achillies was the issue, and he has seen a few specialists and has recieved various treatments, such as been giving support to his feet arches.

I would talk to your gp/find a physio asap.

Don't mean to worry you, but my brother is frustrated by the pain, so much so that he can no longer really run or do exercise involving the lower half of his body, and hes only 25.

I think there is a possiblity of surgery... but that is a long shot, might not work, and could make things work.