Hi. Is your white cell count still low at this time? The Neupogen should raise your white cell counts 24 hours after it was given, so you should have your CBC repeated a full day after, to see if the drug had any effect. If the counts haven't gone back to normal levels, additional doses of Neupogen should be given. Low blood counts, either red or white cells, can cause fatigue. If you're having fatigue due to low red cell counts (anemia), you may also need to have erythropoeitin injections. This is a drug that stimulates red cell production.
Aside from the Neupogen (or other similar drugs), there's no other way to raise white cell counts. But having adequate nutrition will help you recover faster from low blood counts, as well as mitigate the extent of the decrease in counts. If you're not eating enough, high calorie food supplements like Ensure might be helpful.
The pain might be due to the Neupogen. It might also be due to high uric acid levels. As the chemotherapy starts to have an effect and the cancer starts to break apart, a lot of uric acid gets released into the blood stream, and this could cause joint and back pains. If your pain is persistent, you may want to have this checked.
Sorry to hear you're in pain. Chemo is such a harsh treatment and the rescue drugs like neupogen are also hard on your body. Ask your docs for pain meds, they should give you whatever it takes.
Try posting your question on both the Hepatitis C and the Hepatitis Social Community forums, lots of people who post there have taken neupogen and can advise you. There's a lot of traffic on those boards so you'll get an answer sooner.
Your instincts are good, staying hydrated is important so yes, drink lots of fluids. And hang in there, being cancer free is worth it.