Pain from angina (blocked arteries) is surprisingly non-worrying, and so you should always take such pain seriously.
I know, because I had two 99% occlusions in my left anterior descending artery, otherwise known as the "widow maker".
It's called the widow maker because getting a complete blockage is that artery is a non-survivable event. I used to think that prompt and proper CPR could save all heart attack victims, but it turns out that's not the case at all. Some events are more survivable than others.
In my case, I ruptured a plaque while exercising and didn't know it. I didn't feel any pain at all while resting, but if I got up and walked across the room I got what could be best described as what felt like instant indigestion. If I kept moving, my lower jaw would hurt somewhat.
I ignored this pain for several hours before going to the ER. The ER gave me blood tests, an x-ray, and a ECG, and then sent me home because they didn't find anything wrong. They told me to go see a cardiologist.
Being the idiot I was at the time, I didn't schedule an appointment right away, because, after all, I'd just had all that crap done and they didn't find anything.
I waited two days before scheduling an appointment. I went to see the cardiologist, and he said that it was unusual for someone my age (late 30's) to have a blockage, but that what I was describing concerned him. He said that there was no cath lab where I live, and I would have to fly to another place to be seen. He gave my nitroglycerin to take in the mean time for symptoms.
That was another two days.
On day four I showed up at the cath lab, where the cardiologist gave me that, "well, you're too young and healthy for this, but, whatever, we'll check it out," look.
Four hours later after getting my private area shaved and being catheterized, they put two stents in my heart and told me I was lucky to be alive.
Don't ignore chest/arm/jaw/whatever pain. And just because the blood work and xray and whatever else come back negative, don't assume everything is fine.