I could understand it, but barely. Still needs work on the translation, man.
Are you using a computer program, or translating manually? Maybe you should get a proofreader for the final copy. This one's going to scare away potential customers, dude.
It should look more like this.
When sinus headaches turn out to be migraines.
Many people suffering pain in their foreheads and at the base of their skull, are under the misconception that their headaches are caused by sinus trouble, when in fact, it is a migraine.
This false assumption is further reinforced by the fact that:
a. The headache is influenced by weather change.
b. Some of their headaches do include sinus trouble.
c. Some sinus medications do help with the pain.
Just a beginning, but you get the idea.