Whats wrong with me

Patient: Hi, for the past couple of weeks iv been having really painfull headaches and days when i dont i have shooting pains in my head. im tired all the time, and whenever i stand up i get dizzy and light-headed. i find it hard to concentrate, it takes me ages to get to sleep at and i get pains in the bottom of my neck and lower back. Also i found a lump in my right index finger and it was small so i paid no attention to it as you could only feel it when i bent my finger but now its big and has stopped growing. In the time iv been feeling all these iv lost quite alot of weight even though i eat the normal amount. can anyone help explain what is wrong with me

Doctor: