Ay oo, nakaranas ako nito rin around that time, napakainit sa shoulder ko parang may nagsasaksak talaga! It's super common sa third trimester kasi ang weight distribution nagbabago, plus the hormones are making everything more tense, pero since it's one-sided and may tusok-tusok feeling, definitely check with your OB para malaman kung normal lang or if there's something else going on. One of my mum friends had something similar and it turned out to be postural, but it's better safe than sorry, especially pag ganyan ang intensity nito, ha.