I have serious headache and ive been consulting but only injection can help me, tablets works for 2 hours only. where must i get help regarding this issue?

Not enough info!: You don't say where you live, so it's hard to tell you what to do next. But a serious headache that is new or worsening needs to be evaluated in the emergency room now. If you have chronic headaches, you need to be evaluated in person. Start with your primary care doctor who can begin the workup w/appropriate blood tests & CT or MRI of your head, and maybe neck too, and then see a neurologist.

Consulting who?: I hope you have consulted a neurologist, if done, seek another neurologist opinion, what you described requires careful evaluation, with good history and physical examination and probably blood/imaging studies, good luck