Struggling with pronouncing words correctly

For context, I am an international student who has been using English for day-to-day communication for the past couple of years. Recently, I often struggle with pronouncing and enunciating certain words when I speak them out. It's as if my mouth and throat struggle to make those sounds. I've listened to my own recording and found that I indeed didn't pronounce it right. Furthermore, my voice in the recording sounds very flat and calm. Do you guys have any tips on how to improve this? Many Thanks!