"Heart ache" refers to the emotional pain or sadness that someone feels deep within their heart. It can be caused by various reasons such as loss, disappointment, or a broken relationship. Full definition
These simple guidelines may sound a lot like common sense, but they are often missed and will save you a lot of heart aches. (puppy-training-solutions.com)
More than that, the tone of the letter is of one whose heart aches for the apparent lack of love and for the struggles roiling his community, and who writes tenderly to his beloved ones, his little children. (religion-online.org)
Heart aching when we dropped them off at sleepaway camp, thinking the summer would never end. (positivedisciplinect.org)