Can we always expect healing when we pray for it?

First, it may be helpful to ask if the apostles, if Jesus, could heal anyone at will...
 
Luke 5:17 And the power of the Lord was present for him to heal the sick.
 
This would imply that sometimes the power of the Lord was not present to heal. Now faith is not invariably required, either, for healing, Jesus raised a young man from the dead without even being asked (Lk. 7:11-15) and healed the ear of a soldier when he was being arrested (Lk. 22:51).
 
Paul preached to the people in Galatia because of an illness, was he lacking in faith? They did not look down on him for being physically infirm either, and Paul says that was commendable, and does not chide himself for lacking healing then. And Trophimus he left sick at Miletus, and Timothy was instructed to drink a little wine, for his frequent illnesses. And then there was Epaphroditus, who almost died, while being with Paul, and Paul had a doctor who traveled with him (not a used-to-be doctor!). Let us also remember Lazarus...
 
John 11:6  Yet when he heard that Lazarus was sick, he stayed where he was two more days.
 
And let us remember Job, he wasn't healed right away, and he was a righteous man, being tested, and his faith was exemplary (Jas. 5:11).
 
Yes, by Jesus' stripes we are healed, and God can and does heal today, but we cannot simply claim healing, even though this is "the children's bread," if we need it, we will have it, but we may not always need it.
 
Matthew 4:2  After fasting forty days and forty nights, he was hungry‚Ķ
 
But eventually, there will be healing, completely, and bread in both senses is promised as well.
 
Psalm 103:3-5 ... who forgives all your sins and heals all your diseases, who redeems your life from the pit and crowns you with love and compassion, who satisfies your desires with good things so that your youth is renewed like the eagle's.
 
Not all our desires are satisfied right away, nor are all our diseases healed immediately, but they will be...