What Does It Mean When My Bones Hurt When I Get Sick?

I too have the same problem. I believe it's not the bones but the muscles attached to them that hurt. That's due to the lack of nutrition and immobility of the muscles thus they hurt.
Also I noticed that only happens when my body temperature rises above normal. I also get muscle spasms when my temperature goes 40 C or a bit higher.
What you can do about it is get pain reliever tablets or those that stabilize the blood flow thus lowering the body temperature. - Just personal opinion.

You're getting sick is the answer, your bones hurting are the symptoms.