What does it mean when old scars are sore, swollen, and slightly red?

Almost every old scar that I have has become a little swollen and sore to the touch. It's also hard where the scar is. Every scar is at least 6 years old and I've never had any infections, scar tissue, etc.What does it mean when old scars are sore, swollen, and slightly red?
You probably have an infection. Or you may have MRSA.What does it mean when old scars are sore, swollen, and slightly red?
i think u might have infection or something i say that u go 2 ur doctor immediately!!
circle circle dot dot did you get your tetanus shot?