“the condition has length > 1 and only the first element will be used” warning from nested `if elses' over a dataframe

Question

I have a dataframe with two columns, df_headache_tibble:

structure(list(df_questionaire.headaches = c(0L, 2L, 2L, 2L, 
0L, 0L, 0L, 0L, 2L, 0L, 2L, 2L, 0L, 2L,