Hi! I couldn't read and not respond, at 5+1 weeks pregnant (now 27 weeks!) I was in the exact same position as you. I had been playing about with the dogs when the shoulder pain started and I was very anxious about the whole thing.
I called 111 (it was a Friday night) and they assured me I wasn't being a pain, they advised me to go to the primary care centre, where I had my bloods done and they had a look at my shoulder. I was then referred for a scan in the EPU on the following Monday.
When I went for the scan they looked at my blood results for HCG, which they said were really good levels and didn't bother taking a second lot to see about whether they had doubled, instead they decided to go straight for the scan. At first they tried to do an abdominal scan but my uterus is retroverted so I had to have the internal scan, but it was worth it to see that everything was okay! It's possible that they would have been able to see on the abdominal scan if my uterus wasn't retroverted.
I was invited back for a follow up scan at 7+1 where we were able to see a heartbeat (abdominal scan only) before being discharged from the EPU.
It's definitely worth speaking to your GP if you're concerned, in my experience any examinations of your tummy were very gentle and it was only the internal scan and the blood tests (I'm needlephobic) that we're unpleasant for me. Turns out I'd just pulled my shoulder when playing with the dogs, but when you can't get your mind off the alternative, it's hard to concentrate on anything else!
I hope everything goes well for you!