I just found out i have "a 1 centimeter spot" on my lung during a ct. how worried should i be?

Did/ do you smoke?: It depends on whether you ever smoked or if you ever had cancer. If yes to either of these, there is cause for concern. If yes, the next exam should be a pet / ct. This is assuming there are no previous lung ct scans to compare to your current one. If you had a lung ct one or more years ago, you should have the radiologist who read your current scan see if the "spot" was previously present.

Unclear: Spots or nodules in the lungs can mean different things. They could represent sequeli of prior infection or other inflammation. It could also represent an early cancer. Obviously, this needs to be investigated further. Follow up with your doctor.

As your doctor: The term spot is very non specific. You need to talk to your doctor in detail. Ask the impression of the interpreting and potentially consult with a specialist. There are many types of noducles that can form in the lung, benign and malignant. You need the details.

Discuss with doctor: This is one of the situations where you need to sit down with your doctor and have a detailed talk. Most lung spots of this size are not concerning as the majority are not cancers. Depending on risk factors such as age, smoking history, lung problems (emphysema etc), family & work history many of these spots can be followed with repeat ct in a few months.