Does no focal consolidation, no effusion, or obvious pneumothorax in x-ray mean i should not stress myself out about having lung cancer?

Stop worrying: This is good news. Try to stop smoking. One cause of a longstanding cough that baffles doctors is cough-variant asthma -- perhaps you have this. Best wishes.

Probably not cancer: If your only risk factor for lung cancer is 2 months of smoking, the the results you give suggest that there is very low probability of lung cancer. There are limitations to the sensitivity of standard chest x-rays for detection of lung cancer. A ct scan is better at finding tumors early for people ages 55 to 79 who smoked the equivalent of a pack a day for 30 years and continue to smoke.