Healthcare on Chol Hamoed
Is it permitted to make a doctor appointment on Chol Hamoed?
A. Melacha to Relieve Pain
Shulchan Aruch O.C. 532:2 permits healthcare on Chol Hamoed. What remains unclear is whether he permitted it for everyone and whether this permit includes melacha or only taking medicine. Magen Avraham 532:2 writes that Shulchan Aruch permitted taking medicine. This is certainly justified based on the sources for Shulchan Aruch. That is, Shulchan Aruch’s ruling is based on a Tosefta that permits a person to drink medicinal drinks on Chol Hamoed, which is codified by the Rif and Rosh. Magen Avraham implies that only taking medicine is permitted but actual melacha for healthcare is forbidden on Chol Hamoed. This is further supported by the implication in Pri Megadim E”A 532:2 that it is only permitted to do melacha for a chol shein bo sakana, a person who is sick even though it isn’t mortal danger. Mishna Brurah’s (532:5) formulation echoes that of Pri Megadim and implies that melacha is only permitted for someone who is sick, but not just to relieve pain. Pitchei Teshuvot 532:3 is strict.
On the other hand, Rav Moshe (Igrot Moshe OC 3:78:1) implies that it is permitted to do melacha to treat pain on Chol Hamoed. Rav Shlomo Zalman Auerbach (Shemirat Shabbat Kehilchata ch. 66 fnt. 88) also agrees with this.
It seems to emerge that there is a major dispute whether it is permitted to do melacha to relieve pain. However, this understanding is questionable. Chaye Adam’s approach is based on assuming that treating an illness is similar to doing melacha to avoid a dvar ha’aved, a loss. Therefore, that only allows doing melacha for someone who is sick but not to relieve pain. If one were to consider the melacha in terms of tzorech hamoed, a need for the moed, it should be permitted to do unskilled melacha that doesn't involve excessive effort to relieve pain. This is the ruling of Hilchot Chol Hamoed Zichron Shlomo (p. 61 and Biurim 6), even though he is strict for Chaye Adam, Pri Megadim, and Mishna Brurah.
Therefore, it is permitted to do unskilled melacha without excessive effort to relieve pain.
B. Well Visits and Checkups
All of the above is regarding treating an illness or relieving pain, but is it permitted to practice healthcare just to guard one’s health?
Meiri (m"k 10b s.v. makizin) writes that it is permitted to do medical care on Chol Hamoed because that is considered dvar ha'aved. He adds that it is even permitted to treat someone to protect his health even if he's not sick. It isn't clear if he permits melacha for someone who isn't sick, or he only permitted that person to take medicine.
Rav Elyashiv (Hilchot Chol Hamoed Zichron Shlomo p. 62 fnt. 12) allowed a regular cleaning at the dentist during Chol Hamoed. The reason is that he considers this to be included in doing melacha for healthcare that is permitted. Rav Sheinberg (ibid.) goes further and permits scheduling a doctor appointment for Chol Hamoed. His reason is that he compares treating a person’s health to ochel nefesh, preparing food, which is permitted even if he planned to do it on Chol Hamoed. Shemirat Shabbat Kehilchata (ch. 66 fnt. 88) agrees.
However, Rav Moshe (Igrot Moshe 3:78:1) writes that it is forbidden to go to the dentist for a well visit since there the dentist is going to do melacha and there is no reason to permit it. Since a person isn’t in pain there’s no reason to permit the melacha.
Similarly, the Debretziner (Hilchot Chol Hamoed Zichron Shlomo teshuva n. 35) forbids making an appointment with a Jewish doctor for a well visit since the doctor is going to need to do melacha and that is forbidden for someone who is well. Also, it is only permitted to go to a non-Jewish doctor if he didn’t plan to go before the Moed. He may not schedule the visit before the Moed.
C. Elective Surgery
Mishmeret Moed (Rabbi Tzion Boaharon p. 76) writes that it is forbidden to schedule an elective surgery on Chol Hamoed since that inflicts pain on a person on Chol Hamoed, which diminishes his simchat hamoed. This concept that it is forbidden to diminish a person’s simchat hamoed in the Mishna m”k 7a. However, Aruch Hashulchan 532:2 dismisses this concept. He writes that it is permitted to do medical treatment that is painful on Chol Hamoed because of its ultimate purpose.