How can I become a low pitch singer to a high pitch singer?

First off, never try to force out higher notes. If your throat hurts, STOP. It is possible to damage your voice by straining your vocal cords.

The easiest way to increase your range is literally just to sing your C scale from Do to Do, and then going to your C# scale, then up to D, and so on until you've reached your range. Other ways Ты can increase your range is to start Пение any note, sliding down to the lowest note Ты can (comfortably) sing, and then sliding back up to the highest note Ты can (comfortably) sing. Another way I like to increase my range is Пение a song that has a note just out of my range and make it my goal to hit it.

Also, if Ты don't have/know how to play Пианино to do scales, Ты can find Видео on YouTube (and other sites) that have the scales Ты can practice off of. или if Ты don't know how to play the scales, those can also easily be found online and aren't hard to pick up on.