I have a 2 CM calcified lung nodule as per my last x ray, should I be worried?

Depends. The pattern of calcification is important. Lamellar, popcorn, central, and diffuse homogenous calcification are usually benign. Anything else that size is very suspicious.
No. A calcified nodule is benign. One that size is usually a hamartoma, a benign growth of benign tissue.
Probably not. Check your previous chest xrays, if seen on an old chest xray more than 2 years ago, and completely calcified , most likely is benign and nothing to worry.