Last year Dr's suspected I might have had Lung Cancer after having a chest xray for something not relevant. Anyway the chest xray showed a 'mass' on my left lung. 

I was contacted by a heart and lung nurse that explained to me what they saw and that they needed to refer me for a urgent scan..

That took 2 weeks.

Well that scan showed I didn't have a tumor but they said it was a cluster of blood cells (I think that's what they described it as) 

Fast forward a year, 

I have a pain in my left lung (chest) that I can put my finger on. I also feel the pain in my back in the same area. 

I have episodes of feeling breathless and I'm very tired alot of the time. I haven't lost any weight. This has been going on for about 3 weeks now. 

I will book in to see the Dr but my question is, could the 'Cluster of blood cells' they say I have in my lung actually be cancer?