That prayer was sincere and I do pray it still and long for that day when I will be "mature and complete lacking nothing" but over the years my life became one plagued by chronic pain. I do not know if you have much experience with pain but it can make the sweetest person mean. Pain is hard to push through. Yet when it decides to sit with you and become a friend that doesn't leave you have to adjust your life to it.
God reminded me of that prayer I prayed. Looking back now 18 years from the time it started I can see the great gift it was and still is. Because of this constant companion I am forced to live swimming in His grace. As you deal with something like pain you have to humble yourself, you have to die to yourself because if you don't you will become bitter and hard and it is in this dying that we become more like Him.
There is a reason that the Bible says that it is harder for the rich to enter the kingdom of Heaven, it is because they have the greatest temptation to rely upon themselves instead of God or anyone else though God is the one who bestows any gift. It is easy to forget, but in suffering it is easier to cry out to God.
I am a stubborn and independent person by nature. I need to have the constant reminder of His grace in my time of need(which is continually). I need the reminder to keep my eyes focused on eternity and what is coming. This helps you remember to number your days and keep the perspective of what really matters. God's gift of chronic pain is what keeps me anchored to Him. It is the greatest gift. I wonder what He uses in your life? Maybe it is the constant struggle trying to understand your child's diagnosis or maybe those therapy appointments that take up your entire week? Maybe it is temptation to worry about finances or your child's future? What is that thing that will make you hard or force your focus on God?
Though pain is not fun to live with in general, I remember this life is short and each day is a gift. I get to share in Christ's sufferings and I know He is walking this with me. Living with pain helps you see others in pain. It gives you a greater heart of compassion for others thus helping you love others. Pain is a great training tool and so is whatever struggle you are plagued with in this life but take heart because eternity is soon coming and Jesus is coming back for those of us who are found in HIM! Hang on dear one! He gives more grace. Rest in Him for He is at work making all things new.
Father, help us to see even the hard things as grace gifts in our lives that help us to die more to ourselves and look a little more like you. Thank you for the gift of suffering. Help us to see it as a grace gift in making us more like you. Help us to trust you and wait for you, for you are coming soon. In Jesus Name. Amen.