Does God heal to a limited extent?

I have been suffering from a tension headache for about 2 and a half years now. I honestly wish for my tension headache to completely go away, and pray often for this request. Yet, it would seem like my prayers are inefficacious, given its persistence despite 2 and a half years of waiting. That said, I can’t deny that its severity has alleviated quite substantially from its beginning, and thus do not want to discount the possibility of God’s intervention in my situation. The question which puzzles me though, if indeed God is responsible for the alleviation of my tension headache, is why God doesn’t go the whole mile and relieve me completely of tension headache? Why just the half-mile, whereby vestiges of my tension headache lingers? Would it be valid for me to think that there is no God in my healing, which is more to be credited to the natural healing capabilities of the body over the casual elapse of time?

I just don’t want to be presumptuous either way, whether this be presuming God’s benign intervention, or his absolute apathy. But given the persistence of my tension headache, albeit in its alleviated form, my reasoning seems more inclined towards attributing my healing process to impersonal healing capacity of the body, rather than towards God. Unless, it can be thought of that God heals, but only to an extent and not completely. I am just unable to understand the reason though why God would heal in such a limited form, rather than exercise his powers to its ultimate effect of complete healing. All this said, I can’t disprove either that God would heal, but only to a limited extent. But I am more inclined to believe that if God heals, he would heal completely and not in such half-baked measures.