Can you lung cancer if you don't smoke? can you still get lung cancer if you smoked for only 10 years?

Yes to both answers: It takes 20 plus years after you stop smoking for your risk factor from smoking to decrease to the level of the general population. You can get lung cancer is you never smoked but that si quite rare.

Yes and yes: Lung cancer is more common in smokers and miners and asbestos workers and some other inhalants. Some non-smokers still get lung cancer. Smoking at all increases ones risk. Quitting reduces the risk back toward baseline.

Yes: Smoking increases the risk of developing lung cancer significantly but is not the only risk factor for that. There are specific lung cancers that we know of now that are called egfr positive or alk positive adenocarcinoma of the lung that tend to occur more commonly but not exclusively in non-smokers. The longer you smoke the higher the risk.