I do smoke in an average of 6-7 cigarettes a day. So am I a chain smoker?

Probably not. There is no medical definition of a chain smoke although i always considered it to be a person who picks up one cigarette as soon as the last one was completed. You probably are not. Nervertheless, there is no safe level of cigarette smoking and you need to quit.
No. By definition, a chain smoker is someone who lights the next cigarette with the still flaming butt of the last cigarette. Typically this is usually in the 3 pack/day range (60 cigarettes). You are nowhere near that, but this would be a good time to stop, since even 1/3 of a pack causes harm to your lungs, your heart and your overall health. Your level of nicotine addiction is less.