I am 80 years young. I have a significant, limp and discomfort in my right hip when I walk-not pain, just a heavy, tired feeling?

Wear and Tear? Many hip joints get somewhat worn after 80 years. Worth getting it checked out and possibly getting a hip x-ray if it continues to bother you. Symptoms like this in seniors often come and go.
Stenosis? You should see your family md for evaluation and imaging studies of your low back to make sure you don't have narrowing of the spinal canal pinching the nerves of your leg making it feel tired and heavy. He will also be able to check your hip when you are evaluated to rule out problems with it.
Back v. Hip. Either radiating pain from the back ( sciatica or radiculopathy) or possible trochanteric bursitis. Get examined by and orthopedic or spinal orthopedic.