... You write that you are suffering from headaches; you fail, however, to inform me of the doctors' diagnosis.
In the majority of such cases, doctors prescribe pills containing nicotinic acid. It may be worthwhile to ask the doctor about taking this medication — possibly he is already prescribing it.
(Igros Kodesh, Vol. XVI, p. 67)
In reply to your letter in which you write about your state of health — your constant headaches and the swelling at the side of your neck:
As is self-understood, you are to inquire again of a specialist and follow his instructions.
With regard to your headaches:
It is quite possible that they are resulting from your irregular menses; when they become more regular through using the proper medical procedures, then your headaches will lessen, at least somewhat.
(Igros Kodesh, Vol. XVIII, p. 326)
... With regard to the migraine headaches from which you are suffering:
In addition to the new medicines that have appeared lately, among them various compounds of nicotinic acid, it would be advisable for you to obtain a small mezuzah that was checked to assure its kashrus and have it wrapped in a cloth cover within a cloth cover and carry it around with you (understandably, when it is permissible to do so, and not on Shabbos in a public domain).
This will undoubtedly have a beneficial effect on your health. ...
(Igros Kodesh, Vol. X, p. 239)
... You write about your hernia:
Find out from a specialist whether wearing an appropriate belt will suffice; also, try to determine why the hernia recurred. Make your decision in accordance with these two points, and may G-d grant you success.
(Igros Kodesh, Vol. XIV, p. 399)
In reply to your letter ... in which you write about your hernia — that you felt pain prior to the procedure and [now,] even after the procedure, the pain has not completely dissipated:
It is known that the belt that is provided for a hernia needs to be adjusted from time to time in accordance with bodily changes that may occur, from either having gained or lost weight. It is logical to assume that your pains result from the improper fit of your belt, and it would therefore be beneficial for an expert to check the belt and adjust it as necessary.
Surely you observe the three well-known daily lessons that apply to all, those of Chumash, Tehillim and Tanya, as established by my father-in-law, the Rebbe. [If you do not as yet,] at least observe them in the future. Recite as well, on a daily basis, the chapter of Tehillim that is appropriate for your age (e.g., when one becomes bar mitzvah, one begins reciting chapter 14, and every year afterwards one recites the chapter that follows).
It would also be appropriate for you to study Mishnayos on a regular basis — at least one or two Mishnayos a day. It would also be beneficial for you to know several chapters of Mishnayos and at least one chapter of Tanya by heart. ...
(Igros Kodesh, Vol. XIV, p. 51)
With regard to
Tevilas Ezra and the like, when it may [negatively] affect one's health, etc.:
It is known from our Nesiim (others say this in the name of the Baal Shem Tov), that "they take upon themselves the responsibility of a single immersion," i.e., that a single immersion will not be injurious [to one's health].
(Likkutei Sichos, Vol. XVII, p. 481)