Answer:
The spinocerebellar pathway is innervated due to excessive exercising. As a result, she feels pain in her right deltoid muscle.
Step-by-step explanation:
The most likely hypothesis is this. Because the excesive exercising can affect nerve tract, causing a lot of pain, inervated nerves means too much use of them, basically.
In addition, the spinocerebellar tract originates in the spinal cord, and terminates to the ipsilateral of the cerebellum, which means that if the nerve begins left side of the cerebellum, will remain on the left side of the body. So, in this case, the innervated nerve is in the right side, right upper chest and shoulder, which it's a common zone for injuries during exercise.
At last, any heart problem is not probable here, because Lucy has no family history of heart disease.