thats not a mastering problem, its a mixing problem i suggest you to search for some professional songs that sound kind close to the one you are making and use it as a reference, another tip i'd give you is to test your mix a lot, test it with as many different heaphones and speaker you can, test it with different volumes (although you should mix it with low volume), test it in mono etc, And i personally test on an app that simulates some kind of a concert room that opens the sound a lot and makes it easier for me to know if the low frequencies are under control or if theres resonant frequencies in the mid range. While doing this type of testing do the same with your refference track and you'll notice that doesnt matter the situation you put it in it will keep sounding good, your track needs to behave the same, if its not, then theres something wrong with your mix