What Causes Chronic Headaches After Giving Birth To A Baby?

hi iam 27 year old i gave birth to baby 4 months back,from last one month iam getting headache,iam using cinerest pills.its a very bad headache I got a bad headache that started early evening and lasted the whole night. The top of my head on both sides would just throb. If I was walking, I felt ok, but if I sat down or lied down, it hurt worse. I was able to sleep but woke up often from the throbbing. Once morning came, the headache was gone. This went on for about five days. I went to see my ob and she said it was most likely a migraine. On the fifth night, I took excedrin migraine which helped but did not clear the headache completely. On the sixth night, I took a sample of a migraine medicine she gave me called treximet. This medicine seemed to have the opposite effect. It made my head pound so hard for about five hours. No position would help. I could not eat, sit down, lie down, talk, or take care of my children. I finally took a hot shower and some nyquil and was able to sleep. My doctor thought maybe I had a sinus infection and got me a z pack and told me to also take tylenol cold. The headaches are now here all day but are very dull and move around different parts of my head. They are sometimes on top of my head, in the back of my head, or behind my eyes. This is now twelve days straight for the headaches. I also have some neck pain.