Hare Krishna!
All glories to Srila Prabhupada!
As per the message of Bhagavad Gita, we are all individual souls eternally but due to our ignorance or forgetfulness about Krishna, the Supersoul, we have taken these material bodies.
Just like the shirt and coat is different from the actual person, the body is different from the soul. The body is just a covering on the soul like dress covering a person.
This covering or ignorance can be removed immediately by the process of Krishna Consciousness which starts with hearing about Krishna, chanting the Holy Names of Krishna, remembering Krishna and so on.
Regarding karma, Krishna gives us the free will to respond to any situation we are put in. If we perform good karma/ pious actions, we have to take new bodies to enjoy good results. If we perform bad karma/ impious actions, we have to take new bodies to suffer for the bad results. However, we are interested in performing karma or actions which bring no reactions. This is possible only by performing all our actions for the service and pleasure of Krishna, the Supreme Lord by the process of Krishna Consciousness.
The eternal relation of soul with Supersoul can be reestablished by following this process of Krishna Consciousness. By this process, we will also be able to reawaken our love with Krishna, the Supreme Personality of Godhead.
In your service,
Ram Krishna Dasa