Paying people according to the prevailing wages in the region is a normal business practice. Supply and demand determine the value of labor in a capitalist system. What you interpret as “wage discrimination” your employer interprets as reducing costs by finding lower-wage employees. In other words the employer isn’t necessarily discriminating against you, they are paying you a wage in line with wages where you live, because they can easily find other people who take the job at the wage offered.
The ways out are to move to a higher-wage region (a big driver of immigration to the US), or position yourself so that your location isn’t relevant and you get paid based on the value you deliver.
Freelancing is one way to make your location irrelevant, but you have to know how to value your work, and of course you have to deliver. The more specialized skills you can apply to solving problems and adding value, the more you can get paid, and the less your customers will care where you live.