The musicians ability to hear and understand musical concepts is one of their most precious and useful abilities.
If the abilities of the ear are lacking one should strive to develop them. In fact, one should be constantly developing the abilities of the inner ear.
When you listen to music, listen actively. Hear everything and understand it. Pick lines out of the inner harmonies and sing them, write them down and analyze what is happening. Develop a practice of listening to a piece several times – With the intent of choosing a different line or part each time.
Building understand through in depth analysis and transcription. Look at sheet music away from your instrument and strive to hear the music off the page. Sing intervals and harmonies that you might gain deeper esthetic knowledge of them. Pick out the bass part of a piece and sing it. Then the middle voices, etc. As you develop learn to trust your ear. Try improvising with a track and picking out the guide tones by ear. Or playing a melody or countermelody which enhances and outlines what is happening in the piece.
If ear development is difficult at first do not be frustrated. Just take it slow.
Do not try to practice ear training for extended periods of time. I would recommend only 10-15 min sessions. Start small by doing things like singing scales, intervals and triads. Slowly work into more complex places. And of course if you have questions do not hesitate to leave them.