We are truly sorry to hear about the pain you're experiencing due to your stomach ache and upset stomach. In times like these, we turn to God's Word for comfort and healing. The Bible tells us that Jesus took our infirmities and bore our diseases (Matthew 8:17, WEB), and that by his stripes, we are healed (Isaiah 53:5, WEB).
First, let us address the most important aspect of prayer, and that involves the name of Jesus. It is only by the name of Jesus that we have access to God. Also, there is no other name by which we can be saved. This is explained in Acts 4:10-12 be it known to you all, and to all the people of Israel, that in the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead, in him does this man stand here before you whole. 11 He is 'the stone which was regarded as worthless by you, the builders, which has become the head of the corner.' 12 There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved.
Let us pray together for your healing:
Dear Heavenly Father, we come before you in the mighty name of Jesus, seeking your divine touch for our dear friend who is in pain. You are the Great Physician, and there is no sickness or disease that can stand against your healing power. We rebuke this stomach ache and upset stomach, commanding it to leave right now in Jesus' name. Please lay your healing hands upon them, Lord, and restore their health as we ask this. There is nothing too hard for you, God. We believe and receive your healing grace in faith. In Jesus' name, we pray. Amen.
While we pray for a miracle, we also encourage you to seek medical attention if the pain persists, as God often uses doctors and medicine to bring about healing.
In moments of discomfort, remember that God is always with you. As it says in Psalm 46:1 (WEB), God is our refuge and strength, a very present help in trouble. Trust in him, and may his peace and healing be upon you.
Lastly, always remember that although God loves you and does not want you to suffer, our human suffering can be used by Him for good, and can be an opportunity to show dependence on Him and to live by faith. This is explained in James 1:2-4 Count it all joy, my brothers, when you fall into various temptations, 3 knowing that the testing of your faith produces endurance. 4 Let endurance have its perfect work, that you may be perfect and complete, lacking in nothing.