Thank you for writing.
These spots may be lung nodules on the lungs that can be cancerous or benign. A biopsy will need to be done to know what kind you have. I can't say why a biopsy is not being done - perhaps the nodules are tiny and your doctor is waiting for months to see if they change or grow larger. Please address this six month wait with your doctor. - they may be so small he feels it can wait.
We cannot say if you should be worried - this is something you need to address with your doctor, in addition to the waiting time. We wish you the best, I hope it's nothing serious.