Shoulder pain in early pregnancy

Im looking advice on shoulder pain in early pregnancy im almost 6 weeks and this is my 3rd pregnancy and.off course googled about ectopic, i found out last friday being pregnant and didnt think i was and got the hep b vaccine before taken my test, wondering if that could be the cause? Ill be phoning hospital tomorrow but unsure if ill be seen as no other symptoms. The pain does feel like its going into my back and swaps between shoulders. I just get a feeling somethings wrong at times just wanting some reassurance that it could be nothing. I have an early scan booked for 23rd as first available one but unsure if i can wait that long. Ive also just been lounging about some days as waiting to start new job which i need the vaccine for.