The start of a cough…

Hi all, 

I am new here - my diagnosis is on my profile - stage 4 cancer - primary in the lung with brain mets. The lung cancer diagnosis came as a total shock as apart from feeling a bit tired I had no symptoms. I was only diagnosed because of neurological symptoms. I have had surgery for 2 of the three tumours in the brain, and am awaiting a treatment for the 3rd tumour (probably a type of radiotherapy). I am currently on 2mg of dexamethasone a day. 

In the past 24hrs I have developed a sore throat and have also generally had ongoing post nasal drip which has been irritating, but in the last day, this irritation has also prompted me to cough - for the first time. This has made me very nervous and scared as I have had no lung symptoms so far and am scared for what the implications of this could be for the possible support and treatment that is being considered. I’ll call my lung specialist nurse team when they are available today and report in - but I wonder if my fear is warranted that the development of the symptoms will remove treatment options from me. In spite of having stage 4, some treatments had been suggested given that I have a single site of mets, but I had no symptoms when I was told this. I have been pretty good at trying to take one hard piece of information at a time and just focusing on that, but this development has been triggering and I’ve found it harder this morning. So, I am scared and here I am! Any experiences of coping with the development and arrival of lung symptoms would be really helpful… Thank you. 
Val