Wellness or good health is a great mercy from God (Allah in Arabic, Elohim in Hebrew). It does not mean that if a person has a sickness, he is deprived from God’s mercy, sickness may be a hard test from God Almighty to the person to help him or her to develop a strong faith.
God (Allah) has the Higher Power of cure or healing, and all the medical treatments are tools that are used to promote healing and the path to better health. The final decision of complete healing is under the control of God (Allah). In fact, if a person undergoes medical treatment for a particular disease, his or her progress and improvement may or may not be remarkable; however, when he or she starts to ask Allah for help, Allah may cure him or her completely by his Higher Power and Miracles.
Many people when they get an illness such as severe pain, dizziness, digestive trouble, vision problems, convulsions, bleeding, difficulty in breathing, heart failure, fractures, liver failure, tumors, temporary sterility or chronic diseases, etc.; they ask God for mercy and grace of healing. They may spend days and nights meditating while using their medical treatment to accelerate their healing.
Some Muslims believe that if a person suffers from a disease, it may help him or her in the afterlife because it may increase the chance of forgiveness of one’s personal sins by Almighty God (Allah). Some people donate charity in anticipation for the moment when they gain complete healing to thank Allah for the graceful gift of health, and they understand that they should not stop thanking Him every day.
Muslims believe in the Miracles of Allah to the prophet Jesus PBUH.
"And (appoint him) a Messenger to the Children of Israel, ( with this message)": "I have come to you, with a Sign from your Lord, in that I make for you out of clay, as it were the figure of a bird, and breathe into it, and it becomes a bird by Allah’s leave; and I heal those born blind and the lepers, and I quicken the dead, by Allah’s leave; and I declare to you what you eat, and what you store in your houses. Surely therein is a Sign for you if you did believe." Quran 3:49 (Yusuf Ali 2007)
So, to attain wellness, people need to worship the true Almighty God (Allah), not to associate with Him anything, and ask for His blessings, Amen.