Being bi in a heterosexual relationship

Hey everybody. So currently i am in a relationship with a guy and I consider myself bisexual. So me and my bf haven’t had sex yet but, I’m worried I like him and I’m into him but I can’t do blow jobs or hand Jobs for very long with my wrist hurting or my jaw cramping and I shut down. I feel really bad because he is able to get me off but, I can’t get him off without there being a problem. What do I do?