Hi, thanks for writing to HCM.
The description of your symptoms goes in favour of "Neurogenic claudication" which usually results from Lumbar canal stenosis. Pain and heavyness in the calves will also be seen in Vascular claudication but typically the pain should come down once you stop walking.
I suggest you to have a detailed evaluation by an orthopedic surgeon and undergoing MRI
scan that will rule out spinal causes. A general surgeon
should evaluate the vascular status in your limb. Hope this helps