Kim
Sounds similar to a problem I had (but hope not...)
I picked up an achiles problem in Aug'01 (shortly after taking up running !). I stupidly carried on running for a further 8 months, even though it became increasing painful. Saw lots of expensive specialists (be careful !) who all diagnosed scar tissue probs following a tear - but failed to resolve. 2 told me to give up running. I had to pull out of FLM'02 and roll over my entry
A running friend then recommended another sports physio (with misc famous clients I learnt later) who sorted it quite quickly - very, very, painful though (brought tears to my eyes !!!)
He broke-up the tissue using 'deep massage' techniques - basically squeezing, stretching, pinching it where it hurt and was swollen most - plus ultrasound, lots of special stretches etc. 4 weeks of this..
Within days of the first session though things started to improve. I was also told to re-build my running slowly, cut a 'v' shape in the heel tab of my shoes (the cause of the prob possibly - quite high up on the Grid Hurricanes I was wearing then) and massage the thing myself (I used a smooth, flat, pebble + oil !)
In short - it can be fixed, but make sure you see someone who knows about running injuries. Best of luck - think positive !!
t