Worries vs Determination, Hmmmm

Well, I learned today that if I begin Cladribine treatments, I have to stop Interferon for a period. That worries me, because if the Cladribine doesn't work and the growths start again, can we get them stopped a second time? I wonder, too, how my body will react returning to Interferon after having a low blood count. It was difficult to adjust to with a healthy body.
I'm still willing and determined. But, wrestling with these new frets is troublesome.
I, also, have a new "experience". For about 5 months now, I've been having arm pain in my Humeri(?), Humeruses(?), bicep area of both arms any way.:-/ I like to do push-ups during my walks, and it became difficult when, suddenly, this pain started. I did nothing to cause an injury. There are spots in each shoulder which show up on a bone scan I had done in 2007. I wonder if the growth there hasn't progressed. I figured it would be rather stupid to take the chance. So, my doc is scheduling a full body bone scan and MRI of what brain I've got left ;-). We shall see what we shall see! I just need to focus on the fact that God knows what's best because He can see the BIG picture. I trust He knows exactly what He's doing, and I don't argue (He's bigger and stronger than me) :-).