Can strep cause enlarged lymph nodes near the collar bone?

Yes. Bacterial infections, including strep can cause enlarged lymph nodes that are near the site of infection. If that is the cause, if the infection is successfully treated the nodes should shrink back down. Persistently enlarged nodes, or nodes that continue to enlarge need evaluation.
Monitoring Centers. Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells and digested food. Lymph nodes "taste" the lymph for anything bad like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well.