Hi,
Welcome to the forum. I am really glad to help you out. Firstly, you need to get your hemogram done to look for any anemia (low hemoglobin). Anemia is one of the important causes of headache. The possiblity of anemia is more when there are pregnancies at short intervals. Please get your thyroid function tests also done to rule out hypothyroidism. Another possiblity is cervical spondylitis.
You should consult an orthopedic surgeon for the same and seek an opinion. You might need to do x-rays/MRI of the cervical spine to look for the cause of the same. I sincerely hope this helps. Take care.