Prayer can be a powerful force*. I have heard about studies that show people improve when others are praying for them, even if they don't know about the pray-ers. On the other hand, we all know of people who have gotten worse, or even died, despite being prayed for. I am not going to attempt to define prayer, that is way beyond the scope of my expertise. To me, though, prayer is more about trust in the process, than that any specific outcome will occur. If prayer had a direct, 1:1 cause and effect with outcome, none of us would have chronic pain or illness. Our prayers to "make it go away" would have done just that, and we would have been cured. Prayer, then, must have some other purpose.
I would not describe myself as religious, but we do attend Sabbath services at our temple every Friday night, and a shorter service and Torah study session every Saturday morning. One part of these services I find especially meaningful is a prayer for healing. Before we sing this prayer, our Rabbi asks for any names of people we would like to have the congregation pray for. A few times, when I have had a specific issue going on, my husband has mentioned my name. Otherwise, I add my name silently. Many people know I have chronic pain and illness issues, but I don't want to draw attention to myself every week. A good friend has prostate cancer, and also does not want to draw attention to himself. When our Rabbi asks for names, he and I will make eye contact, and incline our heads towards each other, in this way adding each other's names to the list without doing so publicly. Or, if we are sitting near each other, we may gently and unobtrusively tap each other on the arm or leg. Another friend recently started having some major health issues, and we quietly have added her to our little 'prayer circle', though I am not sure she knows this.
I have found this intimate acknowledgement of the need for healing to be very powerful. I wrote a piece last year on the difference between healing and curing. Those of us with chronic illness may never be cured, ie, our illnesses go away, but we can still heal, ie, be more at peace with our illness, and in that way, live better with it. I have some symptoms that never go away, others that may be with me for days or weeks or months, and by the time they dissipate, others have taken their place. (My body is an ever-changing source of amusement.) The prayer for healing reminds me that I am not alone in this journey. I have companions and supports, human and otherwise. That knowledge alone helps me get through the tough times, and meanwhile, the prayer is out there in the Universe, working its good.
*Disclaimer: religion is very personal. My beliefs are my own, and I have no intention of convincing anyone to believe as I do. If I have unintentionally offended anyone by my thoughts shared here, I am sorry. That also was not my intent.