Blood in spit only in the morning

[Chrevier]

Hello Doctor

I have been spitting blood only in the early mornings for a year now. If I wake up late it doesn't happen.

My history goes like this;

I have had teeth surgery for 2 of my teeth. However, one tooth still gives me problems as it sometimes swells but doesn't give pain and has been like that for a year now and I use it normally, however, I am planning on having it removed since it has been operated twice and it seems its going to be like that.

Now the spitting of blood started exactly 5 months after I had done my second teeth surgery and had moved to another country for my studies. The first time it happened I thought it was just blood from my mouth but on the second week it happened again and I noticed its not coming from the mouth since it was mixed with mucus and the same day I went to see a doctor who examined me physically ( breathing pattern etc). The doctor recommended blood tests which all came negative. A week later I went to see a specialists who examined my breathing system and x-ray was done of which all the results were okay. The 2 doctors I have visited all say that they didn't see any cause. The first one suggested that it may be stress or something not to worry about.

Now a few months ago I started having a little pain in my right shoulder of which I went for an x-ray for which the results were okay. I moved to another country 3 months ago and was admitted for malaria ( which was never detected but since the country's guidelines on malaria are very strict if they suspect malaria). During this period I was in the hospital, I was given anti-biotics injections and other medications and I noticed that the pain in my chest disappeared but a month later it came back and so does the spitting.

What would be the cause of this, am still worrying?