Heal and Calf Muscle Pain!!1

HI, I was just wondering if you could give me some advice or reason to why I am having strong pains in my heal and calf muscle?
When I walk it hurts on the bottom of my heal and my calf.
I notice that it is alot worse when I sit for awhile and get up to walk again.
I thought I may have pulled a muscle in my calf but it’s been like this for a while now.
Any answers would be greatly appreciated.
Thanks for your time.Jason