Had tarsal tunnel surgery 2 moths ago and if im sitting for awhile my foot gets very stiff making it hard to walk when I get up, is this normal?

Scar tissue. When the body heals itself from a surgical procedure, scar tissue is formed. This can cause stiffness in the area. After tarsal tunnel surgery, or any surgery, it is important to prevent the negative effects of scar tissue by performing range of motion exercises once your surgeon allows. I would contact your physician.
Stiff foot. After surgery some stiffness is normal as already stated. However , speak to your surgeon about any concerns you have.
Other causes. You need to be examined by physician. There are many reasons for your condition, including nerve compression at your spine. Doctor can sort it out. Sometimes it is as simple as rehab therapy.