Could Heaviness In Chest And Shortness Of Breath Be Due To Chemotherapy For Breast Cancer?

I have bi apical pleural- parenchymal thickening. subpleural nodular opacities are present in my bilateral upper lives, likely secondary to dependent atelectasis- I only know this because I had a PETscan as I have been diagnosed with stage 4 metastic Breast cancer- Symptoms prior to diagnosis were feeling winded more easily - now I m on chemo and feel chest heaviness especially the day right after- find I am more short of breath - not sure if Iits anxiety - r/t chemo( last RBCs 3,99) or findings from PEtscan - any thoughts - also any thoughts to decrease ac ( I e. Sleep with head elevated?)