Shoulder Pain

Hello, One should be careful when reciting the final washing of the hands (mayim acharonim) before Birkat Hamazon (Grace after Meals), and must ensure not to speak or interrupt at all between the washing and the blessing, not even with words of Torah—rather, the blessing should be recited immediately. Similarly, it is advisable to be careful after washing hands before the meal itself, so that there should be no interruption at all between the washing and the blessing of Hamotzi. Sources: See Rabbi Chaim Vital, of blessed memory, in his book Sha'ar HaMitzvot (Parashat Ekev, section "Vehineh Ein"), where he writes that one must not interrupt at all between mayim acharonim and Birkat Hamazon. He relates that once he was before his teacher, of blessed memory, and a man came to him and said that for two days he had suffered intense pain in his shoulder. His teacher looked at him and said the pain came because he interrupted between mayim acharonim and Birkat Hamazon with the recitation of a chapter of Mishnayot, thereby violating the teaching of the Rokeach (Berachot 42a) which mandates immediate blessing after washing water, that is mayim acharonim. Accordingly, the pain appeared in his shoulder, and he felt it there. Therefore, one must be careful not to interrupt between mayim acharonim and Birkat Hamazon even with words of Torah. This is also brought in Kaf HaChaim (Siman 127, Section 1). Similarly, it is good practice to be careful not to interrupt at all between washing hands at the meal and the blessing of Hamotzi, as stated in the Shulchan Aruch, Orach Chaim (Siman 160). Consult there also Kaf HaChaim (Section 1), since there are opinions that consider an immediate blessing after washing hands to apply specifically to mayim rishonim (the initial washing). 

With blessings for a full recovery, Hillel Meirs