Is Anything too Hard for God?

Strong...how do you define this word? Physical strength? Mental or psychological stability? What about tough? I've been told I am strong and tough however some days I feel like the weakest and most selfish person I know.
With lupus, everyday can present a new ache or pain, new levels of exhaustion, and often times great fear of relapse. Many people do not realize how extremely painful lupus can be. The disease itself attacks your organs, sometimes focusing on one particular organ alone. Certain movements and activities can sometimes cause unexplained pain. When I was first diagnosed and starting my medicine I had terrible pain in my feet, ankles, an  elbows. The pain was so severe I could barely walk at some points but would go as fast as it came and I would be able to walk fine a few minutes later. My elbows would hurt so bad that brushing my hair would kill me and vacuuming was out of the question. Lately, working out has made the pains go away however, while I've started to increase the weight I've experienced excruciating  pain under my ribs to the point of being doubled over. This alone scared me to the point of tears because of fear that the lupus is relapsing. This pain I have been experiencing is identical to the pain I had before I was diagnosed but never went to the doctor about. How do you explain some random pain that you aren't really sure where it is exactly or what causes it to a doctor? And just because you have a pain doesn't mean you run to the doctor every time. Many times we have unexplained pain and discomfort so I just told myself that's all it was. This time I knew better. I called my doctor after three days of the pain during lower body workouts with my concern. She said she's worried about exhausting myself to the point it can push me back in my remission. One word came to mind, SCARED!
The religious side of me knows nothing is, nor ever will be too hard for God but the flesh, human side of me struggles with the understanding of his purpose many times. It's a humbling thought to know I have been part of God's plan and upper story from day one, as small and "unimportant" I am to this world but I have to remind myself I am important and part of the great master plan for a reason.  As hard as it is to swallow, diseases and illnesses all happen for a reason and I'm excited to see what the future holds for me and my life. I've had so many people tell me that God can heal me and can cure my body of all these autoimmune diseases...as strange as it may seem, I feel like God doesn't want me "healed". Sometimes it's hard to wrap my mind around the fact that he can, although I know it's possible, but I feel like I'm a better witness and story for him with these issues and struggles I deal with on a daily basis.
Daily I pray for guidance and daily, I feel like God has provided more opportunities than I could ever imagine on my own, whether it be to just make it through the day without having a pity party, which does happen-not often but it does, or by giving me the opportunity to help someone with my story.
I love reading and have begun searching for really great devotions to help me when I'm having a weak moment. One great friend has already recommended one. I would appreciate your feedback as well! :) That's all for tonight. Goodnight!