Hello Your history of illness is incomplete , still there are few question as history of smoking, whistling sounds during breathing , common cold , age , gender etc. But still I will try to solve your problem. Palpitation from last six months may be due to , tension , anxiety or fear or phobia ( psychological ) , if you think this is not a cause then please get in E C G and echocardiogram to sort out this problem or to rule out heart disease. As you mentioned that you are also having phlegm and clogging or blocking , so this may be due to allergic bronchitis ( sometimes patient feels as something is stuck in nose or throat . When such type of patient visit in my clinic I advise them to take monteleukast+ levocterizine ( combo pack ) one or two tablet in day according to severity of symptoms . I also advise my patient to take levofloxacin 750 mg one tablet / day for 5-7 days . Still symptoms present then consult a physician and get his opinion because physical examination is important. Good luck.