Many students will try to use personal connections to get shadowing opportunities. Otherwise, they may waste time waiting for an opportunity to just fall into their lap. Don't be one of those students. You should try going to offices in your area dressed nicely and with a resume. Don't call, going in person demonstrates your motivation infinitely better than a voice on the phone and a note from a receptionist that some kid wants to shadow maybe.
Ask if you can get 30 sec with the doc to ask if you can shadow anyone at that office. Do not be shy and be as flexible as possible with hours. Be willing to shadow THAT DAY if they're free. Offer to volunteer to help clean rooms, or organize stuff, or move stuff, or whatever you can do it get involved and have the opportunity to shadow. Most will not actually ask you to do this, so it's a great way to further demonstrate how important their time is to you.
Urgent care centers, allergy clinics, family med, ophthalmology, sports med and any clinic setting pretty much are all great places to shadow because they're usually more slow-paced than some other specialties so the docs are generally a bit more flexible as far as when they can have students come and watch.
If you show you're motivated and interested (the resume is overkill but it shows you are doing everything you can and lets them know a little about you), almost all non-surgical docs I've met will be happy to let you tag along for a couple hours or even a day or two unless they already have students working with them.
You can even try shadowing a neurosurgeon in clinic or something like that, and then use that rapport to ask if you can watch a surgery. I did that and was able to scrub into a few brain surgeries as an undergrad, which the staff coordinator said had never happened before (super cool btw). So it can pay off if you try hard enough and get a bit of luck.
Just be annoyingly persistent if they say yes (don't expect them to call you, they don't care if you come in) and do whatever it takes to get the hours in. Also if it goes well ask them to recommend another doc they can ask and if you can use their name as a reference. Cold calls/visits are better than no visits.
An important option to consider is to contact your college career center or alumni relations and ask if they have any alumni in the area who are practicing physicians. They should be able to give you names. Go to those offices and mention you're currently going to school there. It will establish a connection with the doc immediately.
By doing these things you will set yourself apart from most of your peers by having a broader experience in the medical field. The more experienced you get shadowing a variety of fields, the more confidently you can say in your interview that medicine is for you, and that's very important.
