There are many things that can cause the type of pain you've experienced. While it's a possibility to consider, an aneurysm is not the most likely cause.
There is a larger likelihood of it being of muscular origin, or the result of a temporarily pinched nerve. I would look more to whether you were peeling a large number of potatoes, folding heavy clothes, washed an encrusted broiling pan, or had lifted a large bag of birdseed on the day before.
There is a good point to double-checking with your cardiologist for unassigned chest, back and shoulder pain (and you should, as you've already contacted him to do), but the fact that you've had heart surgery doesn't mean that each new incident in life is going to be related to your heart. Those types of pain are far more often incidental to other things than an aneurysm.
Nor does having a BAV mean that you will have an aortic aneurysm of any sort. Even among the subset of BAVs who require AVR, the majority do not experience an aortic aneurysm requiring an operation in their lifetime. One way to express the nature of that risk might be: patients who have BAV should be more thoroughly and frequently monitored for aneurysms, and any signs of dilation should be monitored and treated more aggressively than a non-BAV patient.
My point is that it doesn't seem to have been established that you have any measurements or signs that indicate that an aneurysm or even dilation exists. As such, unless your echo or other results do show some indication (a CAT scan or MRA would be nice), I wouldn't become overly concerned at this point. Pursue it, so you can feel confident, but don't anticipate it.
If your valve was a big one (did you happen to get a card or something from the valve company that mentioned the size?), it indicates that the surrounding anatomy is likely to be similarly upsized, as a normal part of human variation. Thus, your aorta may be slightly larger than expected for your size without being aneurystic. Valves don't grow and enlarge with an aortic root aneurysm, so your large valve size doesn't indicate an aneurysm. Valves instead distort in shape (and thus leak) from the enlargement around them, if there is an aneurysm. However, they much more often leak for other reasons, such as mismatched cusps or calcifications.
We're all very sensitive to our hearts, particularly after surgery. Me, too. And it's good to be aware and even vigilant, depending on our individual circumstances. But it's also good to try to apply some of the perspectives that we had before our hearts came knocking at our consciousness to our current aches, pains, and discomforts.
Best wishes,