Hi,
I hope this email finds you well and I hope your mom is feeling better.
My mom was diagnosed with stage IV NSCLC september of 07 and has been on a number of drugs one of which was Tarceva. Tarceva works well for a lot of people and when it does its thing it is an amazing drug. My mom was also experiencing the same fatigue you are describing but no head ache. It got better though after 4-5 weeks.
Everyone is ofcourse different,
Best wishes to you and your mom.
cheers.
FOM