Coughing up phlegm n little blood what could be wrong?

Possibilities. Blood mixed with sputum usually occurs with either bronchitis or pneumonia. Pure blood (hemoptysis) may be more concerning for other problems (heart disease, airway diseases, etc).
Sinus or lungs. This could be primarily a sinus infection or possibly a pneumonia. If you are having "cold" symptoms - stuffy nose, sinus pressure - may be a sinus infection. If you are having fever/chills and tightness in chest, it may be a pneumonia. It could be related to bad reflux or dilated vessels in the esophagus as well... Blood and spit don't mix... I'd get it checked out..

Related Questions

I diagnosed and treated me for whooping cough. Is it normal for me to be coughing up phlegm and blood and having a runny nose with mucus and blood?

Yes. Whooping cough, or pertussis can cause excessive, protracted coughing. Small membranes in the throat may burst with hard coughing and blood may come up with phlegm. You may benefit from meds to supress the cough, especially to help you sleep. Read more...