What Causes Blood In Phlegm And Tight Sensation In The Chest?

My husband for several months now has been at times having small amounts of blood showing up in his spit. He has had a tight feeling in the area of his lungs and becomes light-headed. He has seen a doctor twice. The first time the doctor took a chest X-ray which showed nothing much, maybe a case of bronchitis. He was given an antibiotic and got better. A couple of months later the symptoms reappeared and he was given antibiotics once agin, felt better for a couple of weeks. Symptoms are back again. He has a history of colon cancer, prostrate cancer, and melanoma. All three cancers were surgically removed, and he s been cancer free for a couple of years. They also found his blood manufactures too many red blood cells. So he donates blood as often as the Red Cross allows. I know this is a lot of info. We don t know who we can see for answers. Hope you can help.