Pain in calf and tendons

I am 72yrs old, in fair health using medication to control High BP and Colesterol, I suffer with arthritis in my back, hands, feet etc.
About 4 months ago I developed what I thought was muscle cramping in my right calf. After seeing my GP and completing a course of Physio, I found marginal relief. A few weeks later the symptom returned and I found that I was also getting pain down the length of my leg tendons. This was very much worse first thing in the morning and I thought that this maybe because I had little or no medication left in my system. I take 2 Panadene Forte tabs on going to bed, during the day I try to make do with Paracetamol.
After about one hour of taking medication in the AM and walking my dog for about 30 mins, the pain gets less. I find that sitting down to dinner, TV or at the PC, the pain returns until I again get mobile.
I get the same effect down my left tendons but nowhere as severe.
I have been told to take Magnesium tabs which may help.
I do 3 times daily stretching exercises on both legs as advised.

Can anyone advise me what the problem might be and how to combat it ?
With thanks, Aged One. :(

Have you checked to see how advance your arthritis is from the last time you were diagnosed? That maybe the cause of the pain or maybe you strained something.

Hi Aged One,
I went into your review what ever you are doing according to your physical fitness is appreciable having so many problems but as you specified some medicines that you are using is not correct because using so many medicines is not good for health use the medicines prescribed by a good doctor i think it gives a better result with your physical exercise what you are doing.