Soldering those should be a breeze. How hot of iron/gun are you using? Most the time I have seen people have "sticking issues" is when they don't have enough heat and are melting the solder with the iron and dripping it onto a cold joint. Sometimes it is easier to avoid overheating stuff with a hotter tool that can put the heat in quickly and not give it time to startdissipating into the rest of the components. I use a 100 w gun for almost everything except PCB even if it means I only have to touch the tip to the work for 1 second or so. You might also try tinning the pieces seperately then joining. One of those skills once you master you will never want to use a wire nut, butt connector, or twisting again. Not trying to down on you, just saying if you can't get the joint you described to take, its a matter of skills or heat level over the materials most likely. Flux never hurt either
