Coughing up phlegm n little blood what could be wrong?

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..

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).