Non small cell lung cancer stage 111a. had lobectomy but cancer remains in chest wall and lymph node. what is life expectancy without treatment?

Average is 7 months: I'm glad you're considering saying "No" to treatment, at least for now. You're exercising your right to informed consent, and the truth is that with a low-grade tumor, you may have a few good years even with your other health problems -- which may make treating you more difficult. Your oncologist will give you the odds. It's playing numbers. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3579762/

Variable outcomes: It is not entirely clear whether your cancer is truly stage-3A ( it means completely resected, no residual cancer left behind). If there is indeed some tumor left behind in the chest wall, then there is high risk of recurrence which will likely cause you problems within 6 to 12 months. This can be controlled with radiotherapy combined with chemotherapy. So you should reconsider your decision .