I've had similar experiences as well, so I understand how stressful this is. I've tried calling random stores and introducing myself and asking questions (like what time they close, if they take cash, if they have certain items available). This way you can get some practice saying your name to other people and making conversation with strangers. And if you get more confident with that, you can try to go to stores in person and introduce yourself and ask questions. Bookstores or places that offer samples are great for this. My speech therapist has also told me that for tough words, you can try to lean into the first vowel in the word, rather than the consonant (if there isn't a consonant in the beginning, just ease into the vowel gently). Good luck!