Nothing is miserable but what is thought so. And contrariwise, every estate is happy if a person that bears it will be content. Our view of changing circumstances and contentment is a personal choice. It still matters into you.
The apostle Paul reinforced the idea that the way we view our circumstances is more important than the circumstances themselves. While he too was in prison, he wrote: "I have learned in whatever state I am, to be content" (Phil. 4:11). Both men could be content because they drew their ultimate satisfaction from God, who never changes.
Do you feel chained to difficult circumstances? God can give you contentment. Lasting satisfaction can be found only with Him, for in His presence is fullness of joy; at His right hand are pleasures forevermore (Ps. 16:11). When all you have is God, you have all you need.