Pain in my front shoulder muscle - suggestions? (Hybrid cycle)
DISCLAIMER: This is by no means a definitive answer, but one of the options you may want to look into. Also as this borders on a medical advice, this is only meant to give a kind of guidance, not a prescription. 

So one way to deal with pains caused by a substantial amount of cycling is to get your bike fitted, i.e. measured to see if your seat post is high/low enough for you, your cranks are of correct length and so on. 

In your case you may be leaning too much (or indeed not enough!), which could strain your back and/or shoulders, so it could be the case you need your stem shortened (or otherwise lengthened!). 

I had my stem shortened from 100mm to 90mm due to me leaning too much and getting quite a lot of pain in my shoulder blades. However I've had my bike professionally fitted.