Write an email to each professor like this:
Subject: High school student looking to intern in your lab.
Body:
Dear Prof .....
My name is ..... I am a highschool student at ......
I am really interested in your work on (Clear specific details about the work taken from their college website)
I have read your papers ...... (Pick one or two open access papers that you can download for free).
I have the following questions .... (Ask some good questions)
I would really like to do a short intern project in your lab working on .... (topic from papers) possibly doing experiments ...... (Suggest some experiments similar to the ones in the papers).
Thank you for your time, and I hope to hear back from you.
Best Regards
.....
It's a high bar, but it's your best shot. Remember quality is better than quantity. Five Good emails like this will do better than 100 boilerplate emails.
Also don't get disheartened if the professors don't reply, they are very busy and probably didn't open your email, or possibly don't have the space to take on a high school student.
Also remember that it's not required for high school students to have work experience in labs. You have to demonstrate that youre really good to get an intern project as a high school student. Most people who go on to do STEM degrees and PhDs didn't get work experience in a lab as a high school student.