Do i need to wait until my lung infection clears up before getting a chest x-ray to check for cancer? would the infection mask the cancer on x-ray?

Better to wait : A lung infection can make lung cancer more difficult to detect and could cause a false negative (where a cancer is missed). Many physicians do a follow up chest x-ray with 90 days of treating a pneumonia to be sure the pneumonia clears and to be sure a mass was not missed.

See below: Yes; often changes in chest xray take upto 2 months to completely resolve; if concern for cancer is large enough a ct scan is a better test to evaluate.