tightness in the back of my head and im really worried

i am 15 yrs gonna be 16 in a week , i have been suffering from anxiety aprox 3 years now , i havent took any meds for this or any think like that , but recently im have this tightness in the back of my head and im really worried about it , my anxiety is really at peak and im stressed over family probs and school , but this tightness of my head have me really really worried , i recently found a slight bump in the back of my head right where i have the tightness feeling , worried that it can be something serious , can anyone please help me????????