Humans have 23 pairs of chromosomes because 23 chromosomes come from the father and the other 23 come from the mother, and thus humans end up with 46 chromosomes. With 23 sets, you have two copies of each gene. This is what happens in normal situations. However, in some cases during cell division, there could be more or less that 46 chromosomes.
One set of 23 chromosomes is inherited from the biological mother (from the egg), and the other set is inherited from the biological father (from the sperm). Of the 23 pairs of chromosomes, the first 22 pairs are called "autosomes." The final pair is called the "sex chromosomes."
In a normal diploid cell, there are 24 *different* chromosomes out the total of 46: there are 22 pairs of identical autosomes and 2 non-identical sex chromosomes.
Hope this helps!