What are the causes of intense fear of illness and death, panic, tightness in the chest and throat when remembering death, and lack of sleep? Is there a cure for this?

After piety towards Allah and reliance upon Him, it is recommended to maintain the obligatory prayers and adhere to the prescribed remembrances (adhkar), such as the morning and evening adhkar, and to recite Al-Fatiha, Al-Ikhlas, Al-Mu'awwidhatayn (Al-Falaq and An-Nas), and Ayatul-Kursi after every prayer. It is also recommended to frequently recite the verse: {O mankind, there has to come to you an instruction from your Lord and healing for what is in the breasts and guidance and mercy for the believers.} (Yunus: 57). Furthermore, it is advised to keep company with righteous women and attend gatherings of knowledge and remembrance, and to avoid solitude during travel or overnight stays. One must remember death and know that what has befallen one was not meant to miss one, and that this should be a motivation for action and reliance on Allah, not for fear and despair. It is recommended to contact the counseling department and visit specialized doctors and practitioners of ruqyah sharia.