Struggles comprise first and main then skill building and understanding how to care for your voice and protect it before you have a performance.
As a learner you possibly won’t be able to sing the way you want to i.e., the way your favorite singers can. That is because the song-voice is uniquely specific to each individual’s anatomy and emotional sensibilities. One may have a deeper or higher natural voice, a larger or smaller vocal range and one’s innate vibrato may be very different from their favorite singers.
Some of these factors can be amended with training and knowledge and some are just YOU and that should be celebrated! Sing like YOU and not like Aretha or any of your favorites. They are unique and gifted in their own way and so are you! Be INFLUENCED by the great singers you admire and pay close attention to their singing and have fun with emulating them but DO NOT expect to sound like them. You might be able to get close but it is far more important to develop your own unique style. And more rewarding too.
Also, the forenamed feeling is even a bigger factor in that we use our voice daily to convey emotion; singing is an emotional communication in its purest form. Thus emotional control is key (no pun intended).
Singing obviously is a totally physical act unlike playing and interacting with an inanimate musical instrument (that presents its own challenges).
It is very complicated to explain so I will just skim the surface here. Interestingly many great singers seem to be able to sing effectively right away or with little ramp-up time or formal study while other great singers need more time to develop and grow their skill and confidence (me for example).
Using the voice to produce music is FAR different that using the voice to produce words. Both are based on sound, phonation, and dynamics but are very very different in their physical production.
For learners, one should not view singing as simply ’words with notes.
The singing voice is generated by using the upper airway in a very different way than how it is used in speaking.
The vocalized sound section is sculpted by the upper airway musculature including the tongue to produce melody in coordination with the oral structures to define the melody around a vowel or consonant to produce the lyric(s).
The lungs provide the obvious vocal energy and sound support since a note is a vibration in the air, as are words but again words are produced using the upper airway in a very different manner.
Ok, that is way more than I wanted to write, and enough for now just off the top of my head. And I have to rehearse now since I have performances coming up (I am an accomplished singer).