Baby only calm in swing

[nnaime]

So DS is a little over 2mos now and he only calms down in his swing, he is never comfortable in any position. He used to love being on his tummy but now he wants to start moving and just lifts his head and cries. Is it okay for him to be in his swing so often? Sometimes it's the only way I can get him to sleep too...
I worry that he will get attached to the swing, or be delayed in mobility