For shadowing:
1) Reach out to your own family physician/pediatrician/etc. and ask them if they would be okay with you shadowing them, or if they have a colleague who might be willing to take you on.
2) Do you have any family friends or relatives who are physicians you could shadow?
3) Does your school have a pre-med office? Reach out to them and see if they have any connections for shadowing (for instance, my school had a list of alumni who were physicians willing to take students who wanted to shadow).
Gaining experience in the health field:
1) It might be too late to sign up for one this summer, but you could consider getting a CNA, EMT, or phlebotomy certification and using it (the certification alone won't help you get into med school). Easy way to participate a little in patient care, maybe make some helpful connections with physicians for future shadowing/LORs, and possibly make a little money as well.
2) If this isn't feasible financially or from a time perspective, look into local hospitals, nursing homes, hospice centers, and free clinics for clinical volunteering opportunities. Hospitals are tougher - you're more likely to be doing stuff like answering phones that's not really direct patient contact. IMO my best patient contact experiences were at a free clinic where they trained me to do HIV testing/safe sex counseling, and another one where I was doing diabetes screening and a little counseling on that as well.
Other meaningful med school application experiences you might think about:
1) Research - Check with professors and/or grad students at your school, particularly for classes you performed well in, and see if they're looking for someone to work in their lab. Doesn't have to be hard science either - what matters is that you understand the process of scientific inquiry, whether that's in chemistry or economics.
2) Non-clinical volunteering - identify something you enjoy doing that could be used to help others (teach art classes to seniors, coach basketball at a school with a high free lunch population, play board games at a homeless shelter...you name it). Find a place to do that thing and keep doing it until you apply and/or graduate.