/\/\/\/\ I've had Achilles strain. No fun. I needed a lot of convincing from my physiotherapist that the best way to get through it was (in addition to treatment e.g. certain strengthening exercises, stretches and ice) to "fatigue the hell out of it". It took 3 months of riding, including several FNRttCs, to push through that barrier. It was the York to Hull ride in April 2012 that finally did it. I could not walk at all for 2 days but then, bam, everything started to improve rapidly. Hope you're getting treatment. Best of luck and GWS.
ETA: "it" being the calf muscle. Just to clarify that!