If my boyfriend ejaculates into a wee sample tube and I use a syringe to insert the sperm into myself could I get pregnant if so what are the chances?

Not predictable. Whether you will get pregnant or not depends greatly on ovulation and thus the right time. It also depends on whether your BF's sperms are healthy and in sufficient quantity. There are just too many variables. since even under optimal conditions, not all intercourse leads to pregnancy.