Dull ache in my calfs if DON'T exercise

Hi

I have searched and searched for an answer to this so I would be truly grateful if someone could help. My doctor has simply said 'that's interesting' which is a fat lot of good. I have the strange problem that my calves ache if I do not go to the gym. It's as though I have to stretch them out and only going to the gym and stretching on the weight machines will do. Once I have done this my legs feel fantastic. The problem is I don't want to have to constantly go to the gym. If it's closed for a couple of days my legs start to ache causing me to get grumpy and agitated and I can't got away on holiday to anywhere that doesn't have a gym to stretch my legs.

They particularly ache where the muscle inserts into the knee bit (not an experty at anatomy)

I realise this sounds really weird but I have had for years and am getting completely fed up with it